diff --git a/src/tagstudio/core/library/alchemy/constants.py b/src/tagstudio/core/library/alchemy/constants.py
index aba48a27..71f1bdd4 100644
--- a/src/tagstudio/core/library/alchemy/constants.py
+++ b/src/tagstudio/core/library/alchemy/constants.py
@@ -14,7 +14,7 @@ JSON_FILENAME: str = "ts_library.json"
 
 DB_VERSION_CURRENT_KEY: str = "CURRENT"
 DB_VERSION_INITIAL_KEY: str = "INITIAL"
-DB_VERSION: int = 400
+DB_VERSION: int = 500
 
 TAG_CHILDREN_QUERY = text("""
 WITH RECURSIVE ChildTags AS (
diff --git a/src/tagstudio/core/library/alchemy/db.py b/src/tagstudio/core/library/alchemy/db.py
index e28880c3..332f3551 100644
--- a/src/tagstudio/core/library/alchemy/db.py
+++ b/src/tagstudio/core/library/alchemy/db.py
@@ -9,6 +9,8 @@ import structlog
 from sqlalchemy import Dialect, String, TypeDecorator
 from sqlalchemy.orm import DeclarativeBase
 
+from tagstudio.core.utils.normalization import norm_path
+
 logger = structlog.getLogger(__name__)
 
 
@@ -19,7 +21,7 @@ class PathType(TypeDecorator):
     @override
     def process_bind_param(self, value: Path | None, dialect: Dialect):
         if value is not None:
-            return Path(value).as_posix()
+            return norm_path(Path(value), case_sensitive=True).as_posix()
         return None
 
     @override
diff --git a/src/tagstudio/core/library/alchemy/enums.py b/src/tagstudio/core/library/alchemy/enums.py
index 0c3c55c4..6cf1264b 100644
--- a/src/tagstudio/core/library/alchemy/enums.py
+++ b/src/tagstudio/core/library/alchemy/enums.py
@@ -72,7 +72,10 @@ class ItemType(enum.Enum):
 
 class SortingModeEnum(enum.Enum):
     DATE_ADDED = "file.date_added"
+    DATE_CREATED = "file.date_created"
+    DATE_MODIFIED = "file.date_modified"
     FILE_NAME = "generic.filename"
+    FILE_SIZE = "file.size"
     PATH = "file.path"
     RANDOM = "sorting.mode.random"
 
diff --git a/src/tagstudio/core/library/alchemy/library.py b/src/tagstudio/core/library/alchemy/library.py
index 9797d6b8..b888a157 100644
--- a/src/tagstudio/core/library/alchemy/library.py
+++ b/src/tagstudio/core/library/alchemy/library.py
@@ -12,7 +12,7 @@ from dataclasses import dataclass
 from datetime import UTC, datetime
 from os import makedirs
 from pathlib import Path
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, NamedTuple
 
 import structlog
 from humanfriendly import format_timespan  # pyright: ignore[reportUnknownVariableType]
@@ -28,7 +28,6 @@ from sqlalchemy import (
     create_engine,
     delete,
     desc,
-    exists,
     func,
     inspect,
     or_,
@@ -94,7 +93,8 @@ from tagstudio.core.library.alchemy.models import (
 from tagstudio.core.library.alchemy.visitors import SQLBoolExpressionBuilder
 from tagstudio.core.library.ignore import migrate_ext_list
 from tagstudio.core.library.json.library import Library as JsonLibrary
-from tagstudio.core.utils.stat import get_date_created, get_date_modified
+from tagstudio.core.utils.normalization import norm_path
+from tagstudio.core.utils.stat import get_date_created, get_date_modified, get_file_size
 from tagstudio.core.utils.types import unwrap
 
 if TYPE_CHECKING:
@@ -204,12 +204,22 @@ class LibraryStatus:
     json_migration_req: bool = False
 
 
+class FileStat(NamedTuple):
+    """Cached stat() fields. Matches the ones stored in file entries."""
+
+    date_created: float | None
+    date_modified: float | None
+    file_size: int | None
+
+
 class Library:
     """Class for the Library object, and all CRUD operations made upon it."""
 
     library_dir: Path | None = None
     engine: Engine | None = None
-    included_files: set[Path] = set()
+    path_cache: dict[Path, int] | None = None
+    duplicate_path_entry_ids: list[int] | None = None
+    is_case_sensitive_fs: bool | None = None
 
     def __init__(self) -> None:
         self.dupe_entries_count: int = -1  # NOTE: For internal management.
@@ -222,7 +232,9 @@ class Library:
             self.engine.dispose()
         self.library_dir = None
         self.folder = None
-        self.included_files = set()
+        self.path_cache = None
+        self.duplicate_path_entry_ids = None
+        self.is_case_sensitive_fs = None
 
         self.dupe_entries_count = -1
         self.dupe_files_count = -1
@@ -651,54 +663,84 @@ class Library:
             make_transient(entry)
             return entry
 
-    def refresh_file_entry_stats(self, entry_id: int, path: Path | None):
-        """Updates a file entry's associated stat() data."""
-        needs_update = False
+    def refresh_entries_stats(self, entries: list[tuple[int, Path]]) -> int:
+        """Check and update os.stat() metadata for multiple file entries in bulk.
 
-        entry = self.get_entry_full(entry_id, with_fields=False, with_tags=False)
-        if not entry:
-            return
+        Only file entries that have differing stat data will be updated.
 
-        if not path:
-            full_path = unwrap(self.library_dir) / entry.path
-        else:
-            full_path = unwrap(self.library_dir) / path
+        Args:
+            entries (list[tuple[int, Path]]): A list of (ID, Path) tuples to check.
 
-        file_date_created = get_date_created(full_path)
-        file_date_modified = get_date_modified(full_path)
+        Returns:
+            int: The number of entries that were updated.
+        """
+        if not entries:
+            return 0
 
-        # Log info
-        if entry.date_created != file_date_created:
-            logger.info(full_path)
-            logger.warning(f"Difference in date_created!: {entry.date_created}/{file_date_created}")
-            needs_update = True
-        # else:
-        #     logger.info("No difference in date_created.")
+        library_dir = unwrap(self.library_dir)
+        entry_ids = [entry_id for entry_id, _ in entries]
 
-        if entry.date_modified != file_date_modified:
-            logger.info(full_path)
-            logger.warning(
-                f"Difference in date_modified!: {entry.date_modified}/{file_date_modified}"
+        stored: dict[int, FileStat] = {}
+        with Session(self.engine) as session:
+            for sub_list in [
+                entry_ids[i : i + MAX_SQL_VARIABLES]
+                for i in range(0, len(entry_ids), MAX_SQL_VARIABLES)
+            ]:
+                stmt = select(
+                    Entry.id, Entry.date_created, Entry.date_modified, Entry.file_size
+                ).where(Entry.id.in_(sub_list))
+                for row in session.execute(stmt):
+                    stored[row.id] = FileStat(row.date_created, row.date_modified, row.file_size)
+
+        updates: dict[int, FileStat] = {}
+        for entry_id, path in entries:
+            stored_stat = stored.get(entry_id, FileStat(None, None, None))
+            full_path = library_dir / path
+
+            try:
+                file_stat = full_path.stat()
+            except OSError as e:
+                logger.error(
+                    "[Library] Could not stat file while refreshing entry metadata",
+                    path=full_path,
+                    error=e,
+                )
+                continue
+
+            current_stat = FileStat(
+                get_date_created(file_stat),
+                get_date_modified(file_stat),
+                get_file_size(file_stat),
             )
-            needs_update = True
-        # else:
-        #     logger.info("No difference in date_modified")
 
-        if not needs_update:
-            return
-        else:
-            logger.info(f"Updating entry file_metadata for {full_path}")
+            if stored_stat == current_stat:
+                continue
+
+            logger.info(
+                "[Library] Entry stat data changed",
+                path=full_path,
+                date_created=(stored_stat.date_created, current_stat.date_created),
+                date_modified=(stored_stat.date_modified, current_stat.date_modified),
+                file_size=(stored_stat.file_size, current_stat.file_size),
+            )
+            updates[entry_id] = current_stat
+
+        if not updates:
+            return 0
 
         with Session(self.engine) as session:
-            stmt = update(Entry).where(Entry.id == entry_id)
-            if file_date_created:
-                stmt = stmt.values(date_created=file_date_created)
-            if file_date_modified:
-                stmt = stmt.values(date_modified=file_date_modified)
-
-            session.execute(stmt)
+            session.execute(
+                update(Entry),
+                [
+                    {"id": entry_id, **entry_stat._asdict()}
+                    for entry_id, entry_stat in updates.items()
+                ],
+            )
             session.commit()
 
+        logger.info(f"[Library] Refreshed stat data for {len(updates)} of {len(entries)} entries")
+        return len(updates)
+
     def get_tag_entries(
         self, tag_ids: Iterable[int], entry_ids: Iterable[int]
     ) -> dict[int, set[int]]:
@@ -777,8 +819,47 @@ class Library:
         full_ts_path.mkdir(parents=True, exist_ok=True)
         return False
 
+    def _path_cache_key(self, path: Path) -> Path:
+        case_sensitive = (
+            self.is_case_sensitive_fs if self.is_case_sensitive_fs is not None else True
+        )
+        return norm_path(path, case_sensitive=case_sensitive)
+
+    def _cache_add_path(self, entry_id: int, path: Path) -> None:
+        """Keep the path cache consistent with a newly-added or relinked entry."""
+        if self.path_cache is None:
+            return
+        key = self._path_cache_key(path)
+        if key in self.path_cache:
+            displaced_id = self.path_cache[key]
+            logger.warning(
+                "[Library] Duplicate path discovered in path cache while normalizing path, "
+                "marking displaced entry as unlinked.",
+                path=path,
+                displaced_entry_id=displaced_id,
+                entry_id=entry_id,
+            )
+            if self.duplicate_path_entry_ids is None:
+                self.duplicate_path_entry_ids = []
+            self.duplicate_path_entry_ids.append(displaced_id)
+        self.path_cache[key] = entry_id
+
+    def _cache_remove_entries(self, entry_ids: Iterable[int]) -> None:
+        """Keep the path cache consistent with removed entry ids."""
+        removed = set(entry_ids)
+        if not removed:
+            return
+        if self.path_cache is not None:
+            stale_keys = [key for key, eid in self.path_cache.items() if eid in removed]
+            for key in stale_keys:
+                del self.path_cache[key]
+        if self.duplicate_path_entry_ids:
+            self.duplicate_path_entry_ids = [
+                eid for eid in self.duplicate_path_entry_ids if eid not in removed
+            ]
+
     def add_entries(self, items: list[Entry]) -> list[int]:
-        """Add multiple Entry records to the Library."""
+        """Add multiple entries to the Library."""
         assert items
 
         with Session(self.engine) as session:
@@ -795,6 +876,9 @@ class Library:
             new_ids = [item.id for item in items]
             session.expunge_all()
 
+        for entry_id, item in zip(new_ids, items, strict=True):
+            self._cache_add_path(entry_id, item.path)
+
         return new_ids
 
     def remove_entries(self, entry_ids: list[int]) -> None:
@@ -806,12 +890,40 @@ class Library:
             ]:
                 session.query(Entry).where(Entry.id.in_(sub_list)).delete()
             session.commit()
+        self._cache_remove_entries(entry_ids)
 
     def get_entry_id_from_path(self, path: Path) -> int:
         """Attempt to return an Entry ID given a filepath, else return -1."""
         with Session(self.engine) as session:
             return session.scalar(select(Entry.id).where(Entry.path == path).limit(1)) or -1
 
+    def all_paths_with_ids(self) -> dict[int, Path]:
+        """Bulk fetch every Entry's (id, path). Only used to init the path cache."""
+        with Session(self.engine) as session:
+            rows = session.execute(select(Entry.id, Entry.path)).all()
+            return {row.id: row.path for row in rows}
+
+    def get_or_build_path_cache(self) -> dict[Path, int]:
+        """Return the dict cache of normalized paths -> entry IDs."""
+        if self.path_cache is None:
+            cache: dict[Path, int] = {}
+            duplicates: list[int] = []
+            for entry_id, path in self.all_paths_with_ids().items():
+                key = self._path_cache_key(path)
+                if key in cache:
+                    logger.warning(
+                        "[Library] Duplicate normalized path created while building cache, "
+                        "marking the displaced entry as unlinked.",
+                        path=path,
+                        displaced_entry_id=cache[key],
+                        entry_id=entry_id,
+                    )
+                    duplicates.append(cache[key])
+                cache[key] = entry_id
+            self.path_cache = cache
+            self.duplicate_path_entry_ids = duplicates
+        return self.path_cache
+
     def get_paths(self, limit: int = -1) -> list[str]:
         path_strings: list[str] = []
         with Session(self.engine) as session:
@@ -829,7 +941,8 @@ class Library:
     ) -> SearchResult:
         """Filter library by search query.
 
-        :return: number of entries matching the query and one page of results.
+        Returns:
+            SearchResult: number of entries matching the query and one page of results.
         """
         assert isinstance(search, BrowsingState)
         assert self.library_dir
@@ -867,8 +980,14 @@ class Library:
             match search.sorting_mode:
                 case SortingModeEnum.DATE_ADDED:
                     sort_on = Entry.id
+                case SortingModeEnum.DATE_CREATED:
+                    sort_on = Entry.date_created
+                case SortingModeEnum.DATE_MODIFIED:
+                    sort_on = Entry.date_modified
                 case SortingModeEnum.FILE_NAME:
                     sort_on = func.lower(Entry.filename)
+                case SortingModeEnum.FILE_SIZE:
+                    sort_on = Entry.file_size
                 case SortingModeEnum.PATH:
                     sort_on = func.lower(Entry.path)
                 case SortingModeEnum.RANDOM:
@@ -1128,7 +1247,7 @@ class Library:
 
         Returns True if the action succeeded and False if the path already exists.
         """
-        if self.get_entry_id_from_path(path):
+        if self.get_entry_id_from_path(path) >= 0:
             return False
         if isinstance(entry_id, Entry):
             entry_id = entry_id.id
@@ -1146,6 +1265,9 @@ class Library:
 
             session.execute(update_stmt)
             session.commit()
+
+        self._cache_remove_entries([entry_id])
+        self._cache_add_path(entry_id, path)
         return True
 
     def remove_tag(self, tag_id: int) -> bool:
diff --git a/src/tagstudio/core/library/alchemy/migrations.py b/src/tagstudio/core/library/alchemy/migrations.py
index 5acc31e8..5dde198c 100644
--- a/src/tagstudio/core/library/alchemy/migrations.py
+++ b/src/tagstudio/core/library/alchemy/migrations.py
@@ -24,6 +24,7 @@ from tagstudio.core.library.alchemy.fields import LEGACY_FIELD_MAP, DatetimeFiel
 from tagstudio.core.library.alchemy.joins import TagParent
 from tagstudio.core.library.alchemy.models import Entry, Tag, TagColorGroup, Version
 from tagstudio.core.library.ignore import migrate_ext_list
+from tagstudio.core.utils.normalization import norm_path
 from tagstudio.core.utils.types import unwrap
 from tagstudio.i18n.translations import Translations
 
@@ -101,6 +102,7 @@ class DBMigrations:
             MigrationTo202,  # changes: tag_parents
             MigrationTo300,  # changes: deletes folders
             MigrationTo400,  # changes: add category_exclusions
+            MigrationTo500,  # changes: entries
         ]
         with Session(self.engine) as session:
             for migration in migrations:
@@ -616,3 +618,52 @@ class MigrationTo400(DBMigration):
         """)
         )
         session.flush()
+
+
+class MigrationTo500(DBMigration):
+    version = 500
+
+    @override
+    @classmethod
+    def run(cls, session: Session, library_dir: Path, fmt_log: LoggingMethod):
+        """Migrate DB to DB_VERSION 500."""
+        # Drop date columns that were string based to add new float ones, plus int file_size
+        logger.info(fmt_log("Dropping old entry columns..."))
+        session.execute(text("ALTER TABLE entries DROP COLUMN date_created"))
+        session.execute(text("ALTER TABLE entries DROP COLUMN date_modified"))
+        session.flush()
+        logger.info(fmt_log("Adding new entry columns..."))
+        session.execute(text("ALTER TABLE entries ADD COLUMN date_created REAL"))
+        session.execute(text("ALTER TABLE entries ADD COLUMN date_modified REAL"))
+        session.execute(text("ALTER TABLE entries ADD COLUMN file_size INTEGER"))
+        session.flush()
+
+        # Normalize entry paths to NFD
+        logger.info(fmt_log("Normalizing file entry paths..."))
+        rows = session.execute(text("SELECT id, path FROM entries")).all()
+        entries_by_key: dict[Path, list[tuple[int, str]]] = {}
+        for entry_id, path in rows:
+            nfd_path = norm_path(Path(path), case_sensitive=True)
+            entries_by_key.setdefault(nfd_path, []).append((entry_id, path))
+
+        for nfd_path, group in entries_by_key.items():
+            if len(group) > 1:
+                continue
+
+            entry_id, path = group[0]
+            if path == nfd_path.as_posix():
+                continue  # Already normalized
+
+            session.execute(
+                text(
+                    "UPDATE entries SET path = :path, filename = :filename, "
+                    "suffix = :suffix WHERE id = :id"
+                ),
+                {
+                    "path": nfd_path.as_posix(),
+                    "filename": nfd_path.name,
+                    "suffix": nfd_path.suffix.lstrip(".").lower(),
+                    "id": entry_id,
+                },
+            )
+        session.flush()
diff --git a/src/tagstudio/core/library/alchemy/models.py b/src/tagstudio/core/library/alchemy/models.py
index b357cd45..fb838a29 100644
--- a/src/tagstudio/core/library/alchemy/models.py
+++ b/src/tagstudio/core/library/alchemy/models.py
@@ -17,6 +17,7 @@ from tagstudio.core.library.alchemy.fields import (
     TextField,
 )
 from tagstudio.core.library.alchemy.joins import CategoryExclusion, TagParent
+from tagstudio.core.utils.normalization import norm_path
 
 
 class Namespace(Base):
@@ -204,6 +205,7 @@ class Entry(Base):
     suffix: Mapped[str] = mapped_column()
     date_created: Mapped[float | None]
     date_modified: Mapped[float | None]
+    file_size: Mapped[int | None]
     date_added: Mapped[dt | None]
 
     tags: Mapped[set[Tag]] = relationship(secondary="tag_entries")
@@ -239,19 +241,22 @@ class Entry(Base):
         id: int | None = None,
         date_created: float | None = None,
         date_modified: float | None = None,
+        file_size: int | None = None,
         date_added: dt | None = None,
     ) -> None:
         super().__init__()
-        self.path = path
         self.id = id  # pyright: ignore[reportAttributeAccessIssue]
-        self.filename = path.name
-        self.suffix = path.suffix.lstrip(".").lower()
+        self.path = norm_path(path, case_sensitive=True)  # NFD is enforced
+        self.filename = self.path.name
+        self.suffix = self.path.suffix.lstrip(".").lower()
 
         # The date the file associated with this entry was created.
         # st_birthtime on Windows and Mac, st_ctime on Linux.
         self.date_created = date_created
         # The date the file associated with this entry was last modified: st_mtime.
         self.date_modified = date_modified
+        # The size of the file associated with this entry, in bytes: st_size.
+        self.file_size = file_size
         # The date this entry was added to the library.
         self.date_added = date_added
 
diff --git a/src/tagstudio/core/library/alchemy/registries/unlinked_registry.py b/src/tagstudio/core/library/alchemy/registries/unlinked_registry.py
deleted file mode 100644
index 6b6fa65c..00000000
--- a/src/tagstudio/core/library/alchemy/registries/unlinked_registry.py
+++ /dev/null
@@ -1,98 +0,0 @@
-# SPDX-FileCopyrightText: (c) TagStudio Contributors
-# SPDX-License-Identifier: GPL-3.0-only
-
-
-from collections.abc import Iterator
-from dataclasses import dataclass, field
-from pathlib import Path
-
-import structlog
-from wcmatch import glob, pathlib
-
-from tagstudio.core.library.alchemy.library import Library
-from tagstudio.core.library.alchemy.models import Entry
-from tagstudio.core.library.ignore import PATH_GLOB_FLAGS, Ignore, ignore_to_glob
-from tagstudio.core.utils.types import unwrap
-
-logger = structlog.get_logger()
-
-
-@dataclass
-class UnlinkedRegistry:
-    """State tracker for unlinked entries."""
-
-    lib: Library
-    files_fixed_count: int = 0
-    unlinked_entries: list[Entry] = field(default_factory=list)
-
-    @property
-    def unlinked_entries_count(self) -> int:
-        return len(self.unlinked_entries)
-
-    def reset(self):
-        self.unlinked_entries.clear()
-
-    def refresh_unlinked_files(self) -> Iterator[int]:
-        """Track the number of entries that point to an invalid filepath."""
-        logger.info("[UnlinkedRegistry] Refreshing unlinked files...")
-
-        self.unlinked_entries = []
-        for i, entry in enumerate(self.lib.all_entries()):
-            yield i
-            full_path = unwrap(self.lib.library_dir) / entry.path
-            if not full_path.exists() or not full_path.is_file():
-                self.unlinked_entries.append(entry)
-
-    def match_unlinked_file_entry(self, match_entry: Entry) -> list[Path]:
-        """Try and match unlinked file entries with matching results in the library directory.
-
-        Works if files were just moved to different subfolders and don't have duplicate names.
-        """
-        library_dir = unwrap(self.lib.library_dir)
-        matches: list[Path] = []
-
-        # NOTE: ignore_to_glob() is needed for wcmatch, not ripgrep.
-        ignore_patterns = ignore_to_glob(Ignore.get_patterns(library_dir))
-        for path in pathlib.Path(str(library_dir)).glob(
-            patterns=f"***/{glob.escape(match_entry.path.name)}",
-            flags=PATH_GLOB_FLAGS,
-            exclude=ignore_patterns,
-        ):
-            if path.is_dir():
-                continue
-            if path.name == match_entry.path.name:
-                new_path = Path(path).relative_to(library_dir)
-                matches.append(new_path)
-
-        logger.info("[UnlinkedRegistry] Matches", matches=matches)
-        return matches
-
-    def fix_unlinked_entries(self) -> Iterator[int]:
-        """Attempt to fix unlinked file entries by finding a match in the library directory."""
-        self.files_fixed_count = 0
-        matched_entries: list[Entry] = []
-        for i, entry in enumerate(self.unlinked_entries):
-            yield i
-            item_matches = self.match_unlinked_file_entry(entry)
-            if len(item_matches) == 1:
-                logger.info(
-                    "[UnlinkedRegistry]",
-                    entry=entry.path.as_posix(),
-                    item_matches=item_matches[0].as_posix(),
-                )
-                if not self.lib.update_entry_path(entry.id, item_matches[0]):
-                    try:
-                        match = unwrap(self.lib.get_entry_full_by_path(item_matches[0]))
-                        entry_full = unwrap(self.lib.get_entry_full(entry.id))
-                        self.lib.merge_entries(entry_full, match)
-                    except AttributeError:
-                        continue
-                self.files_fixed_count += 1
-                matched_entries.append(entry)
-
-        for entry in matched_entries:
-            self.unlinked_entries.remove(entry)
-
-    def remove_unlinked_entries(self) -> None:
-        self.lib.remove_entries(list(map(lambda unlinked: unlinked.id, self.unlinked_entries)))
-        self.unlinked_entries = []
diff --git a/src/tagstudio/core/library/ignore.py b/src/tagstudio/core/library/ignore.py
index 63b7ab18..20191c5d 100644
--- a/src/tagstudio/core/library/ignore.py
+++ b/src/tagstudio/core/library/ignore.py
@@ -1,5 +1,5 @@
 # SPDX-FileCopyrightText: (c) TagStudio Contributors
-# SPDX-License-Identifier: GPL-3.0-only
+# SPDX-License-Identifier: MIT
 
 
 from copy import deepcopy
@@ -14,7 +14,7 @@ from tagstudio.core.utils.singleton import Singleton
 
 logger = structlog.get_logger()
 
-PATH_GLOB_FLAGS = glob.GLOBSTARLONG | glob.DOTGLOB | glob.NEGATE | pathlib.MATCHBASE
+PATH_GLOB_FLAGS: int = glob.GLOBSTARLONG | glob.DOTGLOB | glob.NEGATE | pathlib.MATCHBASE
 
 
 GLOBAL_IGNORE = [
diff --git a/src/tagstudio/core/library/refresh.py b/src/tagstudio/core/library/refresh.py
deleted file mode 100644
index a14469c4..00000000
--- a/src/tagstudio/core/library/refresh.py
+++ /dev/null
@@ -1,232 +0,0 @@
-# SPDX-FileCopyrightText: (c) TagStudio Contributors
-# SPDX-License-Identifier: GPL-3.0-only
-
-
-import shutil
-from collections.abc import Iterator
-from dataclasses import dataclass, field
-from datetime import datetime as dt
-from pathlib import Path
-from time import time
-
-import structlog
-from wcmatch import pathlib
-
-from tagstudio.core.library.alchemy.library import Library
-from tagstudio.core.library.alchemy.models import Entry
-from tagstudio.core.library.ignore import PATH_GLOB_FLAGS, Ignore, ignore_to_glob
-from tagstudio.core.utils.silent_subprocess import silent_run  # pyright: ignore
-from tagstudio.core.utils.stat import get_date_created, get_date_modified
-from tagstudio.core.utils.types import unwrap
-
-logger = structlog.get_logger(__name__)
-
-
-@dataclass
-class RefreshTracker:
-    library: Library
-    files_not_in_library: list[Path] = field(default_factory=list)
-
-    @property
-    def files_count(self) -> int:
-        return len(self.files_not_in_library)
-
-    def save_new_files(self) -> Iterator[int]:
-        """Save the list of files that are not in the library."""
-        batch_size = 200
-
-        index = 0
-        while index < len(self.files_not_in_library):
-            yield index
-            end = min(len(self.files_not_in_library), index + batch_size)
-            entries = [
-                Entry(
-                    path=entry_path,
-                    fields=[],
-                    date_created=get_date_created(unwrap(self.library.library_dir) / entry_path),
-                    date_modified=get_date_modified(unwrap(self.library.library_dir) / entry_path),
-                    date_added=dt.now(),
-                )
-                for entry_path in self.files_not_in_library[index:end]
-            ]
-            self.library.add_entries(entries)
-            index = end
-        self.files_not_in_library = []
-
-    def refresh_dir(self, library_dir: Path, force_internal_tools: bool = False) -> Iterator[int]:
-        """Scan a directory for files, and add those relative filenames to internal variables.
-
-        Args:
-            library_dir (Path): The library directory.
-            force_internal_tools (bool): Option to force the use of internal tools for scanning
-                (i.e. wcmatch) instead of using tools found on the system (i.e. ripgrep).
-        """
-        if self.library.library_dir is None:
-            raise ValueError("No library directory set.")
-
-        ignore_patterns = Ignore.get_patterns(library_dir)
-
-        if force_internal_tools:
-            return self.__wc_add(library_dir, ignore_to_glob(ignore_patterns))
-
-        dir_list: list[str] | None = self.__get_dir_list(library_dir, ignore_patterns)
-
-        # Use ripgrep if it was found and working, else fallback to wcmatch.
-        if dir_list is not None:
-            return self.__rg_add(library_dir, dir_list)
-        else:
-            return self.__wc_add(library_dir, ignore_to_glob(ignore_patterns))
-
-    def __get_dir_list(self, library_dir: Path, ignore_patterns: list[str]) -> list[str] | None:
-        """Use ripgrep to return a list of matched directories and files.
-
-        Return `None` if ripgrep not found on system.
-        """
-        rg_path = shutil.which("rg")
-        # Use ripgrep if found on system
-        if rg_path is not None:
-            logger.info("[Refresh: Using ripgrep for scanning]")
-
-            compiled_ignore_path = library_dir / ".TagStudio" / ".compiled_ignore"
-
-            # Write compiled ignore patterns (built-in + user) to a temp file to pass to ripgrep
-            with open(compiled_ignore_path, "w") as pattern_file:
-                pattern_file.write("\n".join(ignore_patterns))
-
-            result = silent_run(
-                " ".join(
-                    [
-                        "rg",
-                        "--files",
-                        "--follow",
-                        "--hidden",
-                        "--ignore-file",
-                        f'"{str(compiled_ignore_path)}"',
-                    ]
-                ),
-                cwd=library_dir,
-                capture_output=True,
-                shell=True,
-                encoding="UTF-8",
-            )
-            try:
-                compiled_ignore_path.unlink()
-            except Exception as e:
-                logger.error(
-                    "[Refresh] Could not remove compiled ignore path",
-                    path=compiled_ignore_path,
-                    error=e,
-                )
-
-            if result.stderr:
-                logger.error(result.stderr)
-
-            return result.stdout.splitlines()  # pyright: ignore [reportReturnType]
-
-        logger.warning("[Refresh: ripgrep not found on system]")
-        return None
-
-    def __rg_add(self, library_dir: Path, dir_list: list[str]) -> Iterator[int]:
-        start_time_total = time()
-        start_time_loop = time()
-        dir_file_count = 0
-        self.files_not_in_library = []
-
-        for r in dir_list:
-            f = pathlib.Path(r)
-
-            end_time_loop = time()
-            # Yield output every 1/30 of a second
-            if (end_time_loop - start_time_loop) > 0.034:
-                yield dir_file_count
-                start_time_loop = time()
-
-            # Skip if the file/path is already mapped in the Library
-            if f in self.library.included_files:
-                dir_file_count += 1
-
-                entry_id = self.library.get_entry_id_from_path(f)
-                self.library.refresh_file_entry_stats(entry_id, path=f)
-
-                continue
-
-            # Ignore if the file is a directory
-            if f.is_dir():
-                continue
-
-            dir_file_count += 1
-            self.library.included_files.add(f)
-
-            # if not self.library.has_entry_with_path(f):
-            #     self.files_not_in_library.append(f)
-            entry_id = self.library.get_entry_id_from_path(f)
-            if entry_id < 0:
-                self.files_not_in_library.append(f)
-            else:
-                self.library.refresh_file_entry_stats(entry_id, path=f)
-
-        end_time_total = time()
-        yield dir_file_count
-        logger.info(
-            "[Refresh]: Directory scan time",
-            path=library_dir,
-            duration=(end_time_total - start_time_total),
-            files_scanned=dir_file_count,
-            tool_used="ripgrep (system)",
-        )
-
-    def __wc_add(self, library_dir: Path, ignore_patterns: list[str]) -> Iterator[int]:
-        start_time_total = time()
-        start_time_loop = time()
-        dir_file_count = 0
-        self.files_not_in_library = []
-
-        logger.info("[Refresh]: Falling back to wcmatch for scanning")
-
-        try:
-            for f in pathlib.Path(str(library_dir)).glob(
-                "***/*", flags=PATH_GLOB_FLAGS, exclude=ignore_patterns
-            ):
-                end_time_loop = time()
-                # Yield output every 1/30 of a second
-                if (end_time_loop - start_time_loop) > 0.034:
-                    yield dir_file_count
-                    start_time_loop = time()
-
-                # Skip if the file/path is already mapped in the Library
-                if f in self.library.included_files:
-                    dir_file_count += 1
-                    relative_path = f.relative_to(library_dir)
-                    entry_id = self.library.get_entry_id_from_path(relative_path)
-                    self.library.refresh_file_entry_stats(entry_id, path=relative_path)
-                    continue
-
-                # Ignore if the file is a directory
-                if f.is_dir():
-                    continue
-
-                dir_file_count += 1
-                self.library.included_files.add(f)
-
-                relative_path = f.relative_to(library_dir)
-
-                # if not self.library.has_entry_with_path(relative_path):
-                #     self.files_not_in_library.append(relative_path)
-                entry_id = self.library.get_entry_id_from_path(relative_path)
-                if entry_id < 0:
-                    self.files_not_in_library.append(relative_path)
-                else:
-                    self.library.refresh_file_entry_stats(entry_id, path=relative_path)
-
-        except ValueError:
-            logger.info("[Refresh]: ValueError when refreshing directory with wcmatch!")
-
-        end_time_total = time()
-        yield dir_file_count
-        logger.info(
-            "[Refresh]: Directory scan time",
-            path=library_dir,
-            duration=(end_time_total - start_time_total),
-            files_scanned=dir_file_count,
-            tool_used="wcmatch (internal)",
-        )
diff --git a/src/tagstudio/core/library/scanners.py b/src/tagstudio/core/library/scanners.py
new file mode 100644
index 00000000..17f567a6
--- /dev/null
+++ b/src/tagstudio/core/library/scanners.py
@@ -0,0 +1,101 @@
+# SPDX-FileCopyrightText: (c) TagStudio Contributors
+# SPDX-License-Identifier: MIT
+
+
+import subprocess
+from collections.abc import Iterator
+from pathlib import Path
+
+import structlog
+from wcmatch import pathlib
+
+from tagstudio.core.constants import TS_FOLDER_NAME
+from tagstudio.core.library.ignore import PATH_GLOB_FLAGS, ignore_to_glob
+from tagstudio.core.utils.ripgrep_status import RipgrepStatus
+from tagstudio.core.utils.silent_subprocess import silent_popen  # pyright: ignore
+
+logger = structlog.get_logger(__name__)
+
+
+def scan_paths(
+    scan_dir: Path, ignore_patterns: list[str], force_internal_scanner: bool = False
+) -> Iterator[Path]:
+    """Scan `scan_dir` for files, yielding each match's path relative to `scan_dir`.
+
+    Uses ripgrep if present on the system, falling back to the internal (wcmatch) scanner
+    otherwise or if `force_internal_scanner` is set.
+    """
+    if not force_internal_scanner and RipgrepStatus.which() is not None:
+        yield from _scan_with_ripgrep(scan_dir, ignore_patterns)
+        return
+    yield from _scan_with_internal_scanner(scan_dir, ignore_patterns)
+
+
+def _scan_with_ripgrep(scan_dir: Path, ignore_patterns: list[str]) -> Iterator[Path]:
+    """Scan for files with ripgrep."""
+    logger.info("[Scanners] Using ripgrep for scanning", path=scan_dir)
+
+    compiled_ignore_path = scan_dir / TS_FOLDER_NAME / ".compiled_ignore"
+    compiled_ignore_path.parent.mkdir(parents=True, exist_ok=True)
+    compiled_ignore_path.write_text("\n".join(ignore_patterns), encoding="utf-8")
+
+    proc: subprocess.Popen[str] | None = None
+    try:
+        proc = silent_popen(
+            ["rg", "--files", "--follow", "--hidden", "--ignore-file", str(compiled_ignore_path)],
+            cwd=scan_dir,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            text=True,
+            encoding="UTF-8",
+        )
+        assert proc.stdout is not None
+        for line in proc.stdout:
+            line = line.rstrip("\n")
+            if not line:
+                continue
+            path = Path(line)
+            if (scan_dir / path).is_dir():
+                continue
+            yield path
+
+        proc.wait()
+        if proc.returncode not in (0, 1):  # 1 == "no matches", still successful
+            logger.error(
+                "[Scanners] ripgrep exited with an error",
+                returncode=proc.returncode,
+                stderr=proc.stderr.read() if proc.stderr else "",
+            )
+    finally:
+        if proc is not None:
+            # Loop finished
+            if proc.stdout is not None:
+                proc.stdout.close()
+            # Still running, but cancelled mid-loop
+            if proc.poll() is None:
+                proc.terminate()
+                proc.wait()
+        try:
+            compiled_ignore_path.unlink(missing_ok=True)
+        except OSError as e:
+            logger.error(
+                "[Scanners] Could not remove compiled ignore path",
+                path=compiled_ignore_path,
+                error=e,
+            )
+
+
+def _scan_with_internal_scanner(scan_dir: Path, ignore_patterns: list[str]) -> Iterator[Path]:
+    """Scan for files with the internal glob-based scanner (wcmatch)."""
+    logger.info("[Scanners] Using internal scanner for scanning", path=scan_dir)
+
+    glob_patterns = ignore_to_glob(ignore_patterns)
+    try:
+        for f in pathlib.Path(str(scan_dir)).glob(
+            "***/*", flags=PATH_GLOB_FLAGS, exclude=glob_patterns
+        ):
+            if f.is_dir():
+                continue
+            yield Path(f).relative_to(scan_dir)
+    except ValueError:
+        logger.error("[Scanners] ValueError while scanning directory with the internal scanner")
diff --git a/src/tagstudio/core/library/sync.py b/src/tagstudio/core/library/sync.py
new file mode 100644
index 00000000..6172741e
--- /dev/null
+++ b/src/tagstudio/core/library/sync.py
@@ -0,0 +1,391 @@
+# SPDX-FileCopyrightText: (c) TagStudio Contributors
+# SPDX-License-Identifier: MIT
+
+
+from collections.abc import Iterator
+from dataclasses import dataclass, field
+from datetime import datetime as dt
+from pathlib import Path
+from time import time
+
+import structlog
+from wcmatch import glob, pathlib
+
+from tagstudio.core.library.alchemy.library import Library
+from tagstudio.core.library.alchemy.models import Entry
+from tagstudio.core.library.ignore import PATH_GLOB_FLAGS, Ignore, ignore_to_glob
+from tagstudio.core.library.scanners import scan_paths
+from tagstudio.core.utils.filesystem import is_fs_case_sensitive
+from tagstudio.core.utils.normalization import norm_path
+from tagstudio.core.utils.stat import get_date_created, get_date_modified, get_file_size
+from tagstudio.core.utils.types import unwrap
+
+logger = structlog.get_logger(__name__)
+
+# Yield progress this often during a loop to avoid overwhelming the UI.
+# TODO: Look into whether or not this can be handled on the UI side.
+YIELD_INTERVAL_SECONDS = 0.034
+
+
+@dataclass
+class LibrarySyncEngine:
+    """Keeps a Library's entries in sync with its content directories on disk."""
+
+    library: Library
+    new_paths: list[Path] = field(default_factory=list)
+    paths_to_restat: list[tuple[int, Path]] = field(default_factory=list)
+    unlinked_entries: list[Entry] = field(default_factory=list)
+    relinked_entries: list[Entry] = field(default_factory=list)
+    manual_relink_count: int = 0
+    cancelled: bool = False
+
+    _scanned_paths: list[Path] = field(default_factory=list, init=False, repr=False)
+    _filename_to_path_map: dict[Path, list[Path]] | None = field(
+        default=None, init=False, repr=False
+    )
+
+    @property
+    def new_file_count(self) -> int:
+        return len(self.new_paths)
+
+    @property
+    def restat_count(self) -> int:
+        return len(self.paths_to_restat)
+
+    @property
+    def unlinked_entries_count(self) -> int:
+        return len(self.unlinked_entries)
+
+    @property
+    def relinked_entries_count(self) -> int:
+        return len(self.relinked_entries)
+
+    def reset(self) -> None:
+        """Clear this engine's scan results."""
+        self.new_paths = []
+        self.paths_to_restat = []
+        self.unlinked_entries = []
+        self.relinked_entries = []
+        self._scanned_paths = []
+        self._filename_to_path_map = None
+
+    def _get_case_sensitivity(self) -> bool:
+        if self.library.is_case_sensitive_fs is None:
+            self.library.is_case_sensitive_fs = is_fs_case_sensitive()
+        return self.library.is_case_sensitive_fs
+
+    def sync_dir(
+        self, library_dir: Path, force_internal_scanner: bool = False
+    ) -> Iterator[tuple[int, int]]:
+        """Scan library directory for files, then reconcile them against the Library's entries.
+
+        - Entries with no matching file on disk are marked as "unlinked"
+            - Automatically relink to appropriate new files on disk where possible
+        - Remaining new files on disk are added as new entires
+        - Remaining unlinked entries are tracked for manual review.
+
+        Yields (searched_count, found_count)
+
+        Args:
+            library_dir (Path): The library directory.
+            force_internal_scanner (bool): Option to force the use of the internal scanner
+                (i.e. wcmatch) instead of third-party tools found on the system (i.e. ripgrep).
+        """
+        self.reset()
+        self.cancelled = False
+
+        case_sensitive = self._get_case_sensitivity()
+        cache = self.library.get_or_build_path_cache()
+        unvisited = set(cache.keys())
+        ignore_patterns = Ignore.get_patterns(library_dir)
+
+        start_time = time()
+        start_time_loop = time()
+        count = 0
+        for raw_path in scan_paths(library_dir, ignore_patterns, force_internal_scanner):
+            if self.cancelled:
+                break
+            count += 1
+            self._scanned_paths.append(raw_path)
+            key = norm_path(raw_path, case_sensitive=case_sensitive)
+            entry_id = cache.get(key)
+            if entry_id is not None:
+                unvisited.discard(key)
+                self.paths_to_restat.append((entry_id, raw_path))
+            else:
+                self.new_paths.append(raw_path)
+
+            if (time() - start_time_loop) > YIELD_INTERVAL_SECONDS:
+                yield count, len(self.new_paths)
+                start_time_loop = time()
+
+        if self.cancelled:
+            yield count, len(self.new_paths)
+            logger.info("[Sync] Directory scan cancelled", path=library_dir, files_scanned=count)
+            return
+
+        unlinked_ids = {cache[key] for key in unvisited}
+        if self.library.duplicate_path_entry_ids:
+            unlinked_ids.update(self.library.duplicate_path_entry_ids)
+        if unlinked_ids:
+            self.unlinked_entries = self.library.get_entries(list(unlinked_ids))
+
+        self._auto_relink_matched_entries(case_sensitive, cache)
+
+        yield count, len(self.new_paths)
+        logger.info(
+            "[Sync] Directory scan complete",
+            path=library_dir,
+            duration=(time() - start_time),
+            files_scanned=count,
+            new_files=len(self.new_paths),
+            unlinked_entries=len(self.unlinked_entries),
+            relinked_entries=len(self.relinked_entries),
+        )
+
+    def save_new_entries(self) -> Iterator[int]:
+        """Save the paths found on disk that don't have a Library entry yet."""
+        batch_size = 200
+        library_dir = unwrap(self.library.library_dir)
+
+        index = 0
+        while index < len(self.new_paths):
+            if self.cancelled:
+                break
+            yield index
+            end = min(len(self.new_paths), index + batch_size)
+            batch = self.new_paths[index:end]
+            entries = []
+            for entry_path in batch:
+                file_stat = (library_dir / entry_path).stat()
+                entries.append(
+                    Entry(
+                        path=entry_path,
+                        fields=[],
+                        date_created=get_date_created(file_stat),
+                        date_modified=get_date_modified(file_stat),
+                        file_size=get_file_size(file_stat),
+                        date_added=dt.now(),
+                    )
+                )
+            self.library.add_entries(entries)  # Path cache is updated in the library
+            index = end
+        self.new_paths = self.new_paths[index:]  # Saved entries are removed from new_paths
+
+    def sync_entry_stats(self) -> Iterator[int]:
+        """Refresh cached os.stat() metadata for entries already known to the Library."""
+        batch_size = 500
+
+        index = 0
+        while index < len(self.paths_to_restat):
+            if self.cancelled:
+                break
+            yield index
+            end = min(len(self.paths_to_restat), index + batch_size)
+            self.library.refresh_entries_stats(self.paths_to_restat[index:end])
+            index = end
+        self.paths_to_restat = self.paths_to_restat[index:]
+
+    def _build_filename_to_path_map(self, case_sensitive: bool) -> dict[Path, list[Path]]:
+        index: dict[Path, list[Path]] = {}
+        for path in self._scanned_paths:
+            key = norm_path(Path(path.name), case_sensitive=case_sensitive)
+            index.setdefault(key, []).append(path)
+        return index
+
+    def _glob_for_filename(self, filename: str, case_sensitive: bool) -> list[Path]:
+        """Search the library directory for files matching `filename`.
+
+        Used only as a fallback when find_relink_candidates() is called without a prior
+        sync_dir() scan in this engine instance to reuse results from.
+        """
+        library_dir = unwrap(self.library.library_dir)
+        ignore_patterns = ignore_to_glob(Ignore.get_patterns(library_dir))
+        target_path = norm_path(Path(filename), case_sensitive=case_sensitive)
+        flags = PATH_GLOB_FLAGS | (0 if case_sensitive else glob.IGNORECASE)
+
+        matches: list[Path] = []
+        for path in pathlib.Path(str(library_dir)).glob(
+            patterns=f"***/{glob.escape(filename)}",
+            flags=flags,
+            exclude=ignore_patterns,
+        ):
+            if path.is_dir():
+                continue
+            candidate = Path(path).relative_to(library_dir)
+            if norm_path(Path(candidate.name), case_sensitive=case_sensitive) == target_path:
+                matches.append(candidate)
+        return matches
+
+    def find_relink_candidates(self, entry: Entry) -> list[Path]:
+        """Try to find files in the library directory matching an unlinked entry's filename.
+
+        Comparisons are made using NFD normalization and the assumed filesystem's case sensitivity.
+        """
+        case_sensitive = self._get_case_sensitivity()
+        target_key = norm_path(Path(entry.path.name), case_sensitive=case_sensitive)
+
+        if self._scanned_paths:
+            if self._filename_to_path_map is None:
+                self._filename_to_path_map = self._build_filename_to_path_map(case_sensitive)
+            matches = list(self._filename_to_path_map.get(target_key, []))
+        else:
+            matches = self._glob_for_filename(entry.path.name, case_sensitive)
+
+        logger.info("[Sync] Relink candidates", entry=entry.path.as_posix(), matches=matches)
+        return matches
+
+    def _apply_relink(
+        self, entry: Entry, new_path: Path, cache: dict[Path, int], case_sensitive: bool
+    ) -> bool:
+        """Assign `new_path` to the `entry`, merging into a single entry if entries exist for both.
+
+        Returns:
+            bool: True if the relink was successful.
+        """
+        new_key = norm_path(new_path, case_sensitive=case_sensitive)
+
+        existing_id = cache.get(new_key)
+        if existing_id is not None and existing_id != entry.id:
+            # Merge both entries into one with the single path
+            target = unwrap(self.library.get_entry_full(existing_id))
+            source = unwrap(self.library.get_entry_full(entry.id))
+            return self.library.merge_entries(source, target)
+        return self.library.update_entry_path(entry.id, new_path)
+
+    def relink_unlinked_entries(self) -> Iterator[int]:
+        """Attempt to fix unlinked entries by finding a single matching file in the library."""
+        self.manual_relink_count = 0
+        case_sensitive = self._get_case_sensitivity()
+        cache = self.library.get_or_build_path_cache()
+        matched: list[Entry] = []
+
+        for i, entry in enumerate(self.unlinked_entries):
+            yield i
+            candidates = self.find_relink_candidates(entry)
+            if len(candidates) != 1:
+                continue
+            new_path = candidates[0]
+            if not self._apply_relink(entry, new_path, cache, case_sensitive):
+                continue
+
+            self.manual_relink_count += 1
+            matched.append(entry)
+            logger.info(
+                "[Sync] Relinked entry",
+                entry=entry.path.as_posix(),
+                new_path=new_path.as_posix(),
+            )
+
+        for entry in matched:
+            self.unlinked_entries.remove(entry)
+
+    def _auto_relink_matched_entries(self, case_sensitive: bool, cache: dict[Path, int]) -> None:
+        """Attempt to automatically relink unlinked entries under available conditions.
+
+        Auto-relink applies to:
+            - Files with the same filename but different paths
+                - Handles moves, moves + changes
+            - Files with different names and/or paths but the same date_modified and file_size
+                - Handles moves, renames + moves
+
+        Auto-relink DOES NOT apply to:
+            - Renames + Moves + Changes
+            - Deletions
+            - Ambiguous (more than one) matches
+        """
+        if not self.new_paths or not self.unlinked_entries:
+            return
+
+        library_dir = unwrap(self.library.library_dir)
+
+        # Pass 1: Filename + metadata
+        by_name_and_stat: dict[tuple[Path, float | None, int | None], list[Entry]] = {}
+        for entry in self.unlinked_entries:
+            name_key = norm_path(Path(entry.path.name), case_sensitive=case_sensitive)
+            by_name_and_stat.setdefault(
+                (name_key, entry.date_modified, entry.file_size), []
+            ).append(entry)
+
+        relinked: list[Entry] = []
+        remaining_new: list[Path] = []
+        stats_by_path: dict[Path, tuple[float | None, int | None]] = {}
+
+        for new_path in self.new_paths:
+            try:
+                file_stat = (library_dir / new_path).stat()
+            except OSError as e:
+                logger.error(
+                    "[Sync] Could not stat file during auto-relink check",
+                    path=new_path,
+                    error=e,
+                )
+                remaining_new.append(new_path)
+                continue
+
+            mtime = get_date_modified(file_stat)
+            size = get_file_size(file_stat)
+            stats_by_path[new_path] = (mtime, size)
+
+            name_key = norm_path(Path(new_path.name), case_sensitive=case_sensitive)
+            key = (name_key, mtime, size)
+            candidates = by_name_and_stat.get(key, [])
+            if len(candidates) != 1:
+                remaining_new.append(new_path)
+                continue
+
+            entry = candidates[0]
+            if not self._apply_relink(entry, new_path, cache, case_sensitive):
+                remaining_new.append(new_path)
+                continue
+            by_name_and_stat[key] = []  # Don't match a second new_path here
+
+            logger.info(
+                "[Sync] Automatically relinked moved file",
+                old_path=entry.path.as_posix(),
+                new_path=new_path.as_posix(),
+            )
+            relinked.append(entry)
+
+        for entry in relinked:
+            self.unlinked_entries.remove(entry)
+
+        # Pass 2: Different filename checking for same metadata
+        by_stat_only: dict[tuple[float | None, int | None], list[Entry]] = {}
+        for entry in self.unlinked_entries:
+            by_stat_only.setdefault((entry.date_modified, entry.file_size), []).append(entry)
+
+        still_remaining: list[Path] = []
+        for new_path in remaining_new:
+            stat_key = stats_by_path.get(new_path)
+            if stat_key is None:
+                still_remaining.append(new_path)
+                continue
+
+            candidates = by_stat_only.get(stat_key, [])
+            if len(candidates) != 1:
+                still_remaining.append(new_path)
+                continue
+
+            entry = candidates[0]
+            if not self._apply_relink(entry, new_path, cache, case_sensitive):
+                still_remaining.append(new_path)
+                continue
+            by_stat_only[stat_key] = []
+
+            logger.info(
+                "[Sync] Automatically relinked renamed file (matched by size/date only)",
+                old_path=entry.path.as_posix(),
+                new_path=new_path.as_posix(),
+            )
+            relinked.append(entry)
+            self.unlinked_entries.remove(entry)
+
+        self.new_paths = still_remaining
+        self.relinked_entries = relinked
+
+    def remove_unlinked_entries(self) -> None:
+        """Remove unlinked entries from the Library."""
+        # Path cache is updated in the library.
+        self.library.remove_entries([entry.id for entry in self.unlinked_entries])
+        self.unlinked_entries = []
diff --git a/src/tagstudio/core/utils/filesystem.py b/src/tagstudio/core/utils/filesystem.py
new file mode 100644
index 00000000..42526608
--- /dev/null
+++ b/src/tagstudio/core/utils/filesystem.py
@@ -0,0 +1,15 @@
+# SPDX-FileCopyrightText: (c) TagStudio Contributors
+# SPDX-License-Identifier: MIT
+
+
+import platform
+
+
+def is_fs_case_sensitive() -> bool:
+    """Whether the filesystem is case sensitive.
+
+    NOTE: Not authoritative for OSes other than Windows.
+    """
+    # TODO: Make this more robust instead of assuming Windows == NTFS/exFAT
+    # and other OS filesystems are automatically case sensitive.
+    return platform.system() != "Windows"
diff --git a/src/tagstudio/core/utils/normalization.py b/src/tagstudio/core/utils/normalization.py
new file mode 100644
index 00000000..3ba17230
--- /dev/null
+++ b/src/tagstudio/core/utils/normalization.py
@@ -0,0 +1,16 @@
+# SPDX-FileCopyrightText: (c) TagStudio Contributors
+# SPDX-License-Identifier: MIT
+
+
+import unicodedata
+from pathlib import Path
+
+
+def norm_path(path: Path | str, case_sensitive: bool) -> Path:
+    """Return `path` normalized to Unicode Normalization Form D (NFD)."""
+    if isinstance(path, str):
+        path = Path(path)
+    normalized = unicodedata.normalize("NFD", path.as_posix())
+    if not case_sensitive:
+        normalized = normalized.casefold()
+    return Path(normalized)
diff --git a/src/tagstudio/core/utils/stat.py b/src/tagstudio/core/utils/stat.py
index 7ee46300..cafd71d4 100644
--- a/src/tagstudio/core/utils/stat.py
+++ b/src/tagstudio/core/utils/stat.py
@@ -1,16 +1,28 @@
 # SPDX-FileCopyrightText: (c) TagStudio Contributors
 # SPDX-License-Identifier: MIT
 
+import os
 import platform
 from pathlib import Path
 
 
-def get_date_modified(path: Path) -> float:
-    return path.stat().st_mtime
+def _resolve(path_or_stat: Path | os.stat_result) -> os.stat_result:
+    if isinstance(path_or_stat, os.stat_result):
+        return path_or_stat
+    return path_or_stat.stat()
 
 
-def get_date_created(path: Path) -> float:
+def get_date_modified(path_or_stat: Path | os.stat_result) -> float:
+    return _resolve(path_or_stat).st_mtime
+
+
+def get_date_created(path_or_stat: Path | os.stat_result) -> float:
+    stat = _resolve(path_or_stat)
     if platform.system() in {"Windows", "Darwin"}:
-        return path.stat().st_birthtime
+        return stat.st_birthtime
     else:
-        return path.stat().st_ctime
+        return stat.st_ctime
+
+
+def get_file_size(path_or_stat: Path | os.stat_result) -> int:
+    return _resolve(path_or_stat).st_size
diff --git a/src/tagstudio/qt/controllers/banner.py b/src/tagstudio/qt/controllers/banner.py
new file mode 100644
index 00000000..cf6ba5ef
--- /dev/null
+++ b/src/tagstudio/qt/controllers/banner.py
@@ -0,0 +1,245 @@
+# SPDX-FileCopyrightText: (c) TagStudio Contributors
+# SPDX-License-Identifier: GPL-3.0-only
+
+
+import time
+from collections.abc import Callable
+from typing import Literal, override
+
+from PySide6.QtCore import (
+    QEasingCurve,
+    QPropertyAnimation,
+    QRectF,
+    Qt,
+    QTimer,
+    QVariantAnimation,
+    Signal,
+)
+from PySide6.QtGui import QColor, QPainter, QPainterPath, QPaintEvent
+from PySide6.QtWidgets import QVBoxLayout, QWidget
+
+from tagstudio.qt.views.banner_view import BannerView
+from tagstudio.qt.views.styles.stylesheets import (
+    BANNER_CORNER_RADIUS,
+    banner_notice_bg_color,
+    banner_notice_style,
+    banner_progress_bg_color,
+    banner_progress_chunk_color,
+    banner_progress_style,
+)
+
+BannerMode = Literal["progress", "notice", "fleeting_notice"]
+
+
+class _BannerBackground(QWidget):
+    """The banner's background widget. Used for custom animations, like fading the color."""
+
+    def __init__(self, parent: QWidget | None = None) -> None:
+        super().__init__(parent)
+        self._bg_color = QColor(Qt.GlobalColor.transparent)
+
+    @property
+    def bg_color(self) -> QColor:
+        return self._bg_color
+
+    def set_bg_color(self, color: QColor) -> None:
+        self._bg_color = color
+        self.update()
+
+    @override
+    def paintEvent(self, event: QPaintEvent) -> None:
+        del event
+        painter = QPainter(self)
+        painter.setRenderHint(QPainter.RenderHint.Antialiasing)
+        path = QPainterPath()
+        path.addRoundedRect(QRectF(self.rect()), BANNER_CORNER_RADIUS, BANNER_CORNER_RADIUS)
+        painter.fillPath(path, self._bg_color)
+        painter.end()
+
+
+class Banner(QWidget):
+    """A notification banner with an optional progress bar, action button, and close button."""
+
+    CONTENT_HEIGHT = 36
+    GAP = 6
+    HEIGHT = CONTENT_HEIGHT + GAP
+    ANIMATION_MS = 250
+    COLOR_ANIMATION_MS = 250
+    MIN_VISIBLE_MS = 3000
+    STARTUP_EXTRA_HOLD_MS = 500  # Starting up may eat into time shown, so add extra time.
+
+    notice_action_clicked = Signal()
+    cancel_requested = Signal()
+    dismissed = Signal()
+
+    def __init__(self, parent: QWidget | None = None):
+        super().__init__(parent)
+        self.setMinimumHeight(0)
+        self.setMaximumHeight(0)
+
+        outer_layout = QVBoxLayout(self)
+        outer_layout.setContentsMargins(0, 0, 0, self.GAP)
+        outer_layout.setSpacing(0)
+
+        self._background = _BannerBackground(self)
+        self._background.setObjectName("banner")
+        self.view = BannerView()
+        self._background.setLayout(self.view)
+        outer_layout.addWidget(self._background)
+
+        self._mode: BannerMode = "progress"
+        self._progress_phase: object = None
+        self._notice_style = banner_notice_style()
+        self._progress_style = banner_progress_style()
+        self._notice_bg_color = banner_notice_bg_color()
+        self._progress_bg_color = banner_progress_bg_color()
+        self._background.setStyleSheet(self._notice_style)
+        self._background.set_bg_color(self._notice_bg_color)
+        self.view.progress_bar.set_corner_radius(BANNER_CORNER_RADIUS)
+        self.view.progress_bar.set_chunk_color(banner_progress_chunk_color())
+
+        self._card_color_anim = QVariantAnimation(self)
+        self._card_color_anim.setDuration(self.COLOR_ANIMATION_MS)
+        self._card_color_anim.setEasingCurve(QEasingCurve.Type.OutCubic)
+        self._card_color_anim.valueChanged.connect(self._background.set_bg_color)
+
+        self._connect_callbacks()
+        self._set_mode("notice")
+
+        self._height_anim = QPropertyAnimation(self, b"maximumHeight", self)
+        self._height_anim.setDuration(self.ANIMATION_MS)
+        self._height_anim.setEasingCurve(QEasingCurve.Type.OutCubic)
+        self._height_anim.valueChanged.connect(self.setMinimumHeight)
+
+        self._shown_at: float | None = None
+        self._extra_hold_ms = 0
+        self._hide_timer = QTimer(self)
+        self._hide_timer.setSingleShot(True)
+        self._hide_timer.timeout.connect(lambda: self._start_height_animation(0))
+
+    def request_extra_duration(self) -> None:
+        """Add STARTUP_EXTRA_HOLD_MS to the next automatic hide's minimum-visible window."""
+        self._extra_hold_ms = self.STARTUP_EXTRA_HOLD_MS
+
+    def call_when_open(self, callback: Callable[[], None]) -> None:
+        """Call `callback` if/when the banner is fully open."""
+        if self.maximumHeight() == self.HEIGHT and self._height_anim.state() != (
+            QPropertyAnimation.State.Running
+        ):
+            callback()
+            return
+
+        def _on_finished() -> None:
+            self._height_anim.finished.disconnect(_on_finished)
+            callback()
+
+        self._height_anim.finished.connect(_on_finished)
+
+    def _connect_callbacks(self) -> None:
+        self.view.close_button.clicked.connect(self._on_dismiss)
+        self.view.action_button.clicked.connect(self._on_action_clicked)
+
+    def _on_action_clicked(self) -> None:
+        self.notice_action_clicked.emit()
+
+    def _start_height_animation(self, target_height: int) -> None:
+        if self.maximumHeight() == target_height and self._height_anim.state() != (
+            QPropertyAnimation.State.Running
+        ):
+            return
+        self._height_anim.stop()
+        self._height_anim.setStartValue(self.maximumHeight())
+        self._height_anim.setEndValue(target_height)
+        self._height_anim.start()
+
+    def _animate_to(self, target_height: int, force: bool = False) -> None:
+        self._hide_timer.stop()
+        if target_height > 0:
+            self._shown_at = time.monotonic()
+            self._start_height_animation(target_height)
+            return
+
+        extra_hold_ms = self._extra_hold_ms
+        self._extra_hold_ms = 0
+        if not force and self._shown_at is not None:
+            elapsed_ms = (time.monotonic() - self._shown_at) * 1000
+            remaining_ms = (self.MIN_VISIBLE_MS + extra_hold_ms) - elapsed_ms
+            if remaining_ms > 0:
+                self._hide_timer.start(int(remaining_ms))
+                return
+        self._shown_at = None
+        self._start_height_animation(0)
+
+    def _set_mode(self, mode: BannerMode):
+        if mode == self._mode:
+            return
+
+        self._mode = mode
+        self._progress_phase = None
+        self.view.label.reset_width()
+        self.view.close_button.setVisible(mode != "fleeting_notice")
+        self.view.action_button.setVisible(mode == "notice")
+        self.view.progress_bar.setVisible(mode == "progress")
+
+        # The progress bar state gets a darkened background, while notices get the accent color.
+        is_progress = mode == "progress"
+        self._background.setStyleSheet(self._progress_style if is_progress else self._notice_style)
+
+        target_color = self._progress_bg_color if is_progress else self._notice_bg_color
+        self._card_color_anim.stop()
+        self._card_color_anim.setStartValue(self._background.bg_color)
+        self._card_color_anim.setEndValue(target_color)
+        self._card_color_anim.start()
+
+    def _present(self, mode: BannerMode, button_text: str, message: str) -> None:
+        """Applies the banner mode and any label + button text, then animates the banner open."""
+        self._set_mode(mode)
+        self.view.action_button.setText(button_text)
+        self.view.label.setText(message)
+        self._animate_to(self.HEIGHT)
+
+    def _on_dismiss(self):
+        if self._mode == "progress":
+            self.cancel_requested.emit()
+        # Explicit dismiss, apply immediately
+        self._animate_to(0, force=True)
+        self.dismissed.emit()
+
+    def show_notice(self, message: str, action_text: str) -> None:
+        """Show a dismissible notice with an action button, until dismissed or replaced."""
+        self._present("notice", action_text, message)
+
+    def show_fleeting_notice(self, message: str) -> None:
+        """Show a brief notice with no action button that dismisses itself automatically."""
+        self._set_mode("fleeting_notice")
+        self.view.label.setText(message)
+        self._animate_to(self.HEIGHT)
+        # Deferred by the existing MIN_VISIBLE_MS guard, same as an unforced hide_banner().
+        self._animate_to(0)
+
+    def show_progress(self, text: str, value: int = 0, maximum: int = 0, phase: str | None = None):
+        """Show the progress banner.
+
+        Args:
+            text (str): The status text shown in the banner body.
+            value (int): The current progress value.
+            maximum (int): The maximum progress value. If 0, shown as indeterminate.
+            phase (str | None): An identifier for the current sub-phase of progress.
+                Helps inform widgets that need to update between phases, like the StableLabel.
+        """
+        self._set_mode("progress")
+        if phase != self._progress_phase:
+            self._progress_phase = phase
+            self.view.label.reset_width()
+        self.view.label.setText(text)
+        self.view.progress_bar.set_range(0, maximum)
+        self.view.progress_bar.set_value(value)
+        self._animate_to(self.HEIGHT)
+
+    def hide_banner(self, force: bool = False):
+        """Hide the banner (if shown).
+
+        Args:
+            force (bool): Bypass the minimum visible duration and hide immediately.
+        """
+        self._animate_to(0, force=force)
diff --git a/src/tagstudio/qt/controllers/inspector.py b/src/tagstudio/qt/controllers/inspector.py
index 4e98c546..ebeacc38 100644
--- a/src/tagstudio/qt/controllers/inspector.py
+++ b/src/tagstudio/qt/controllers/inspector.py
@@ -158,7 +158,8 @@ class Inspector(QWidget):
         if stats.duration is not None:
             self._current_stats.duration = stats.duration
 
-        self.layout().file_attrs.update_stats(filepath, self._current_stats)
+        entry = unwrap(self._lib.get_entry(self._selected[0]))
+        self.layout().file_attrs.update_stats(filepath, self._current_stats, entry)
 
     def _set_selection_callback(self) -> None:
         with catch_warnings(record=True):
@@ -257,8 +258,8 @@ class Inspector(QWidget):
                 if update_preview:
                     stats: FileAttributeData = self.layout().preview_thumb.display_file(filepath)
                     self._current_stats = stats
-                    self.layout().file_attrs.update_stats(filepath, stats)
-                self.layout().file_attrs.update_date_label(filepath)
+                    self.layout().file_attrs.update_stats(filepath, stats, entry)
+                self.layout().file_attrs.update_date_label(entry)
                 self.layout().containers.update_from_entry(entry_id)
                 self._set_selection_callback()
 
diff --git a/src/tagstudio/qt/controllers/main_window.py b/src/tagstudio/qt/controllers/main_window.py
index 98eeb4ba..5632fd37 100644
--- a/src/tagstudio/qt/controllers/main_window.py
+++ b/src/tagstudio/qt/controllers/main_window.py
@@ -40,6 +40,7 @@ from tagstudio.core.enums import ShowFilepathOption
 from tagstudio.core.library.alchemy.enums import SortingModeEnum
 from tagstudio.i18n.platform_strings import trash_term
 from tagstudio.i18n.translations import Translations
+from tagstudio.qt.controllers.banner import Banner
 from tagstudio.qt.controllers.inspector import Inspector
 from tagstudio.qt.helpers.mnemonics import assign_mnemonics
 from tagstudio.qt.mixed.landing import LandingWidget
@@ -64,7 +65,7 @@ class MainMenuBar(QMenuBar):
     save_library_backup_action: QAction
     settings_action: QAction
     open_on_start_action: QAction
-    refresh_dir_action: QAction
+    sync_library_action: QAction
     close_library_action: QAction
 
     edit_menu: QMenu
@@ -152,17 +153,17 @@ class MainMenuBar(QMenuBar):
 
         self.file_menu.addSeparator()
 
-        # Refresh Directories
-        self.refresh_dir_action = QAction(Translations["menu.file.refresh_directories"], self)
-        self.refresh_dir_action.setShortcut(
+        # Sync Library
+        self.sync_library_action = QAction(Translations["menu.file.sync_library"], self)
+        self.sync_library_action.setShortcut(
             QtCore.QKeyCombination(
                 QtCore.Qt.KeyboardModifier(QtCore.Qt.KeyboardModifier.ControlModifier),
                 QtCore.Qt.Key.Key_R,
             )
         )
-        self.refresh_dir_action.setStatusTip("Ctrl+R")
-        self.refresh_dir_action.setEnabled(False)
-        self.file_menu.addAction(self.refresh_dir_action)
+        self.sync_library_action.setStatusTip("Ctrl+R")
+        self.sync_library_action.setEnabled(False)
+        self.file_menu.addAction(self.sync_library_action)
 
         self.file_menu.addSeparator()
 
@@ -485,6 +486,7 @@ class MainWindow(QMainWindow):
         # initialized in setup_entry_list
         self.entry_list_container: QWidget
         self.entry_list_layout: QVBoxLayout
+        self.banner: Banner
         self.entry_scroll_area: QScrollArea
         self.thumb_grid: QWidget
         self.thumb_layout: ThumbGridLayout
@@ -691,6 +693,9 @@ class MainWindow(QMainWindow):
         self.thumb_grid.setLayout(self.thumb_layout)
         self.entry_scroll_area.setWidget(self.thumb_grid)
 
+        self.banner = Banner()
+        self.entry_list_layout.addWidget(self.banner)
+
         self.entry_list_layout.addWidget(self.entry_scroll_area)
 
         self.landing_widget = LandingWidget(driver, self.devicePixelRatio())
@@ -698,6 +703,7 @@ class MainWindow(QMainWindow):
 
         self.pagination = Pagination()
         self.entry_list_layout.addWidget(self.pagination)
+
         self.content_splitter.addWidget(self.entry_list_container)
 
     def setup_preview_panel(self, driver: QtDriver):
diff --git a/src/tagstudio/qt/controllers/relink_entries_progress.py b/src/tagstudio/qt/controllers/relink_entries_progress.py
index 9aae5056..0a09f7ad 100644
--- a/src/tagstudio/qt/controllers/relink_entries_progress.py
+++ b/src/tagstudio/qt/controllers/relink_entries_progress.py
@@ -4,7 +4,7 @@
 
 from PySide6.QtCore import QObject, Signal
 
-from tagstudio.core.library.alchemy.registries.unlinked_registry import UnlinkedRegistry
+from tagstudio.core.library.sync import LibrarySyncEngine
 from tagstudio.i18n.translations import Translations
 from tagstudio.qt.controllers.progress_bar import ProgressWidget
 
@@ -12,7 +12,7 @@ from tagstudio.qt.controllers.progress_bar import ProgressWidget
 class RelinkUnlinkedEntriesProgress(QObject):
     done = Signal()
 
-    def __init__(self, tracker: UnlinkedRegistry):
+    def __init__(self, tracker: LibrarySyncEngine):
         super().__init__()
         self.tracker = tracker
 
@@ -22,7 +22,7 @@ class RelinkUnlinkedEntriesProgress(QObject):
                 "entries.unlinked.relink.attempting",
                 index=x,
                 unlinked_count=self.tracker.unlinked_entries_count,
-                fixed_count=self.tracker.files_fixed_count,
+                fixed_count=self.tracker.manual_relink_count,
             )
 
         pw = ProgressWidget(
@@ -32,4 +32,6 @@ class RelinkUnlinkedEntriesProgress(QObject):
             maximum=self.tracker.unlinked_entries_count,
         )
         pw.setWindowTitle(Translations["entries.unlinked.relink.title"])
-        pw.from_iterable_function(self.tracker.fix_unlinked_entries, displayed_text, self.done.emit)
+        pw.from_iterable_function(
+            self.tracker.relink_unlinked_entries, displayed_text, self.done.emit
+        )
diff --git a/src/tagstudio/qt/controllers/rounded_progress_bar.py b/src/tagstudio/qt/controllers/rounded_progress_bar.py
new file mode 100644
index 00000000..2dc0ae5c
--- /dev/null
+++ b/src/tagstudio/qt/controllers/rounded_progress_bar.py
@@ -0,0 +1,236 @@
+# SPDX-FileCopyrightText: (c) TagStudio Contributors
+# SPDX-License-Identifier: GPL-3.0-only
+
+
+import time
+from typing import override
+
+from PySide6.QtCore import QEasingCurve, QRectF, Qt, QTimer, QVariantAnimation
+from PySide6.QtGui import (
+    QColor,
+    QHideEvent,
+    QLinearGradient,
+    QPainter,
+    QPainterPath,
+    QPaintEvent,
+    QResizeEvent,
+    QShowEvent,
+)
+from PySide6.QtWidgets import QWidget
+
+
+class RoundedProgressBar(QWidget):
+    """A custom stylized progress bar that supports smooth animations and rounded corners."""
+
+    MARQUEE_FRACTION = 0.5
+    MARQUEE_INTERVAL_MS = 8
+    MARQUEE_CYCLE_MS = 2000
+    VALUE_ANIMATION_MS = 150
+    FADE_MS = 2000
+
+    def __init__(self, parent: QWidget | None = None) -> None:
+        super().__init__(parent)
+        self._minimum = 0
+        self._maximum = 0
+        self._value = 0
+
+        self._displayed_value = 0.0
+        self._corner_radius = 0.0
+        self._chunk_color = QColor(Qt.GlobalColor.transparent)
+        self._marquee_start: float | None = None
+        self._cached_path: QPainterPath | None = None
+
+        self._opacity = 1.0
+        self._pending_range_change = False
+
+        self._marquee_timer = QTimer(self)
+        self._marquee_timer.setTimerType(Qt.TimerType.PreciseTimer)
+        self._marquee_timer.setInterval(self.MARQUEE_INTERVAL_MS)
+        self._marquee_timer.timeout.connect(self.update)
+
+        self._value_anim = QVariantAnimation(self)
+        self._value_anim.setDuration(self.VALUE_ANIMATION_MS)
+        self._value_anim.setEasingCurve(QEasingCurve.Type.OutCubic)
+        self._value_anim.valueChanged.connect(self._on_value_anim_changed)
+        self._value_anim.finished.connect(self._on_value_anim_finished)
+
+        self._fade_anim = QVariantAnimation(self)
+        self._fade_anim.setDuration(self.FADE_MS)
+        self._fade_anim.setEasingCurve(QEasingCurve.Type.OutCubic)
+        self._fade_anim.valueChanged.connect(self._on_fade_anim_changed)
+
+    def _on_value_anim_changed(self, value: float) -> None:
+        self._displayed_value = value
+        self.update()
+
+    def _on_value_anim_finished(self) -> None:
+        """Start the fade-out once the progress bar has reached its maximum."""
+        if not self._is_indeterminate() and self._value >= self._maximum:
+            self._fade_anim.stop()
+            self._fade_anim.setStartValue(self._opacity)
+            self._fade_anim.setEndValue(0.0)
+            self._fade_anim.start()
+
+    def _on_fade_anim_changed(self, value: float) -> None:
+        """Update the fill opacity for the fade animation."""
+        self._opacity = value
+        self.update()
+
+    def _reset_fade(self) -> None:
+        """Stop any fading and reset opacity back to full."""
+        self._fade_anim.stop()
+        if self._opacity != 1.0:
+            self._opacity = 1.0
+            self.update()
+
+    def set_range(self, minimum: int, maximum: int) -> None:
+        """Set the value range, switching to indeterminate mode if maximum <= minimum."""
+        if (minimum, maximum) == (self._minimum, self._maximum):
+            return
+
+        self._pending_range_change = True
+        self._minimum = minimum
+        self._maximum = maximum
+        if self._is_indeterminate():
+            self._reset_fade()
+        self._sync_marquee_timer()
+        self.update()
+
+    def set_value(self, value: int) -> None:
+        """Animate the fill towards `value`."""
+        self._value = value
+        if self._is_indeterminate():
+            self._pending_range_change = False
+            return
+        if self._pending_range_change:
+            self._pending_range_change = False
+            if value >= self._maximum:
+                self._value_anim.stop()
+                self._displayed_value = float(self._maximum)
+                self.update()
+                self._on_value_anim_finished()
+                return
+
+            self._displayed_value = float(self._minimum)
+            self._reset_fade()
+        elif value < self._maximum:
+            self._reset_fade()
+        self._value_anim.stop()
+        self._value_anim.setStartValue(self._displayed_value)
+        self._value_anim.setEndValue(float(value))
+        self._value_anim.start()
+
+    def set_corner_radius(self, radius: float) -> None:
+        """Set the bottom corner radius and invalidate the cached QPainterPath."""
+        self._corner_radius = radius
+        self._cached_path = None
+        self.update()
+
+    def set_chunk_color(self, color: QColor) -> None:
+        """Set the fill color."""
+        self._chunk_color = color
+        self.update()
+
+    def _is_indeterminate(self) -> bool:
+        """Whether the bar is in indeterminate (marquee) mode."""
+        return self._maximum <= self._minimum
+
+    def _sync_marquee_timer(self) -> None:
+        """Start or stop the marquee timer to match the current mode/visibility."""
+        if self._is_indeterminate() and self.isVisible():
+            if self._marquee_start is None:
+                self._marquee_start = time.monotonic()
+            if not self._marquee_timer.isActive():
+                self._marquee_timer.start()
+        else:
+            self._marquee_timer.stop()
+            self._marquee_start = None
+
+    def _marquee_fraction(self) -> float:
+        """Return the marquee's current position as a fraction of its cycle."""
+        if self._marquee_start is None:
+            return 0.0
+        elapsed_ms = (time.monotonic() - self._marquee_start) * 1000
+        return (elapsed_ms % self.MARQUEE_CYCLE_MS) / self.MARQUEE_CYCLE_MS
+
+    @override
+    def showEvent(self, event: QShowEvent) -> None:
+        """Resume the marquee timer when the bar becomes visible."""
+        super().showEvent(event)
+        self._sync_marquee_timer()
+
+    @override
+    def hideEvent(self, event: QHideEvent) -> None:
+        """Stop all animations and reset state when the bar is hidden."""
+        super().hideEvent(event)
+        self._marquee_timer.stop()
+        self._marquee_start = None
+        self._value_anim.stop()
+        self._reset_fade()
+        self._pending_range_change = False
+
+    @override
+    def resizeEvent(self, event: QResizeEvent) -> None:
+        super().resizeEvent(event)
+        self._cached_path = None  # Invalidate the cached QPainterPath on resize
+
+    def _bottom_rounded_path(self, rect: QRectF) -> QPainterPath:
+        """Return the bottom-rounded clip path for `rect`."""
+        if self._cached_path is not None:
+            return self._cached_path
+
+        # TODO: Currently these values are hardcoded for use with the Banner widget, but this
+        # could be made customizable to specify the exact rounding configuration.
+        # If you're reading this and want to make use of this progress bar, there you go.
+        radius = max(0.0, min(self._corner_radius, rect.width() / 2))
+        diam = radius * 2
+        path = QPainterPath()
+        path.moveTo(rect.left(), rect.top())
+        path.lineTo(rect.right(), rect.top())
+        path.lineTo(rect.right(), rect.bottom() - radius)
+        path.arcTo(QRectF(rect.right() - diam, rect.bottom() - diam, diam, diam), 0, -90)
+        path.lineTo(rect.left() + radius, rect.bottom())
+        path.arcTo(QRectF(rect.left(), rect.bottom() - diam, diam, diam), -90, -90)
+        path.closeSubpath()
+        self._cached_path = path
+        return path
+
+    def _marquee_gradient(self, full_chunk_rect: QRectF) -> QLinearGradient:
+        """Gradient for the indeterminate marquee mode (Transparent -> Color -> Transparent)."""
+        gradient = QLinearGradient(full_chunk_rect.left(), 0, full_chunk_rect.right(), 0)
+        transparent = QColor(self._chunk_color)
+        transparent.setAlpha(0)
+        gradient.setColorAt(0.0, transparent)
+        gradient.setColorAt(0.5, self._chunk_color)
+        gradient.setColorAt(1.0, transparent)
+        return gradient
+
+    @override
+    def paintEvent(self, event: QPaintEvent) -> None:
+        del event
+        # Paint the marquee or normal chunk fill, clipped to the rounded bottom corners.
+        rect = QRectF(self.rect())
+
+        if self._is_indeterminate():
+            chunk_width = rect.width() * self.MARQUEE_FRACTION
+            travel = rect.width() * (1 + self.MARQUEE_FRACTION)
+            chunk_left = (self._marquee_fraction() * travel) - chunk_width
+            full_chunk_rect = QRectF(chunk_left, 0, chunk_width, rect.height())
+            chunk_rect = full_chunk_rect.intersected(rect)
+            if chunk_rect.isEmpty():
+                return
+            fill = self._marquee_gradient(full_chunk_rect)
+        else:
+            fraction = (self._displayed_value - self._minimum) / (self._maximum - self._minimum)
+            fraction = max(0.0, min(1.0, fraction))
+            chunk_rect = QRectF(0, 0, rect.width() * fraction, rect.height()).intersected(rect)
+            if chunk_rect.isEmpty():
+                return
+            fill = self._chunk_color
+
+        painter = QPainter(self)
+        painter.setRenderHint(QPainter.RenderHint.Antialiasing)
+        painter.setClipPath(self._bottom_rounded_path(rect))
+        painter.setOpacity(self._opacity)
+        painter.fillRect(chunk_rect, fill)
+        painter.end()
diff --git a/src/tagstudio/qt/controllers/stable_label.py b/src/tagstudio/qt/controllers/stable_label.py
new file mode 100644
index 00000000..067d2d4a
--- /dev/null
+++ b/src/tagstudio/qt/controllers/stable_label.py
@@ -0,0 +1,38 @@
+# SPDX-FileCopyrightText: (c) TagStudio Contributors
+# SPDX-License-Identifier: GPL-3.0-only
+
+
+from typing import override
+
+from PySide6.QtCore import QSize, Qt
+from PySide6.QtWidgets import QLabel, QWidget
+
+
+class StableLabel(QLabel):
+    """A QLabel that resists "jiggling" from rapidly changing text.
+
+    Holds its `sizeHint()` width at the widest shown since the last reset_width() call,
+    and is always kept left aligned of that, so a centering layout's box stops
+    growing/shrinking on every update (aka the "jiggle" effect).
+    """
+
+    def __init__(self, text: str = "", parent: QWidget | None = None) -> None:
+        super().__init__(text, parent)
+        self.setAlignment(Qt.AlignmentFlag.AlignLeft | Qt.AlignmentFlag.AlignVCenter)
+        self._min_width = 0
+
+    def reset_width(self) -> None:
+        """Let the tracked width shrink again, for new unrelated text."""
+        self._min_width = 0
+        self.updateGeometry()
+
+    @override
+    def setText(self, text: str) -> None:
+        super().setText(text)
+        self._min_width = max(self._min_width, super().sizeHint().width())
+        self.updateGeometry()
+
+    @override
+    def sizeHint(self) -> QSize:
+        hint = super().sizeHint()
+        return QSize(max(hint.width(), self._min_width), hint.height())
diff --git a/src/tagstudio/qt/mixed/drop_import_modal.py b/src/tagstudio/qt/mixed/drop_import_modal.py
index 85909758..6f54c592 100644
--- a/src/tagstudio/qt/mixed/drop_import_modal.py
+++ b/src/tagstudio/qt/mixed/drop_import_modal.py
@@ -178,7 +178,7 @@ class DropImportModal(QWidget):
         pw.from_iterable_function(
             self.copy_files,
             displayed_text,
-            self.driver.add_new_files_callback,
+            self.driver.sync_library_callback,
             self.deleteLater,
         )
 
diff --git a/src/tagstudio/qt/mixed/file_attributes.py b/src/tagstudio/qt/mixed/file_attributes.py
index cb595bd5..b4136fd0 100644
--- a/src/tagstudio/qt/mixed/file_attributes.py
+++ b/src/tagstudio/qt/mixed/file_attributes.py
@@ -3,7 +3,6 @@
 
 
 import os
-import platform
 import typing
 from dataclasses import dataclass
 from datetime import datetime as dt
@@ -17,6 +16,7 @@ from PySide6.QtWidgets import QLabel, QVBoxLayout, QWidget
 
 from tagstudio.core.enums import ShowFilepathOption
 from tagstudio.core.library.alchemy.library import Library
+from tagstudio.core.library.alchemy.models import Entry
 from tagstudio.core.library.ignore import Ignore
 from tagstudio.core.media_types import MediaTypes
 from tagstudio.core.query_lang.file_groups import SEARCH
@@ -92,40 +92,35 @@ class FileAttributes(QWidget):
         self.library = library
         self.driver = driver
 
-    def update_date_label(self, filepath: Path | None = None) -> None:
+    def _format_date_or_na(self, timestamp: float | None) -> str:
+        if timestamp is None:
+            return "<i>N/A</i>"
+        return self.driver.settings.format_datetime(dt.fromtimestamp(timestamp))
+
+    def update_date_label(self, entry: Entry | None = None) -> None:
         """Update the "Date Created" and "Date Modified" file property labels."""
-        if filepath and filepath.is_file():
-            created: dt
-            if platform.system() == "Windows" or platform.system() == "Darwin":
-                # NOTE: Accessing stat().st_birthtime causes linter checks to fail on some systems.
-                created = dt.fromtimestamp(filepath.stat().st_birthtime)  # type: ignore[attr-defined, unused-ignore]
-            else:
-                created = dt.fromtimestamp(filepath.stat().st_ctime)
-            modified: dt = dt.fromtimestamp(filepath.stat().st_mtime)
-            self.date_created_label.setText(
-                f"<b>{Translations['file.date_created']}:</b>"
-                + f" {self.driver.settings.format_datetime(created)}"
-            )
-            self.date_modified_label.setText(
-                f"<b>{Translations['file.date_modified']}:</b> "
-                f"{self.driver.settings.format_datetime(modified)}"
-            )
-            self.date_created_label.setHidden(False)
-            self.date_modified_label.setHidden(False)
-        elif filepath:
-            self.date_created_label.setText(
-                f"<b>{Translations['file.date_created']}:</b> <i>N/A</i>"
-            )
-            self.date_modified_label.setText(
-                f"<b>{Translations['file.date_modified']}:</b> <i>N/A</i>"
-            )
-            self.date_created_label.setHidden(False)
-            self.date_modified_label.setHidden(False)
-        else:
+        if entry is None:
             self.date_created_label.setHidden(True)
             self.date_modified_label.setHidden(True)
+            return
 
-    def update_stats(self, filepath: Path | None = None, stats: FileAttributeData | None = None):
+        created_text = self._format_date_or_na(entry.date_created)
+        modified_text = self._format_date_or_na(entry.date_modified)
+        self.date_created_label.setText(
+            f"<b>{Translations['file.date_created']}:</b> {created_text}"
+        )
+        self.date_modified_label.setText(
+            f"<b>{Translations['file.date_modified']}:</b> {modified_text}"
+        )
+        self.date_created_label.setHidden(False)
+        self.date_modified_label.setHidden(False)
+
+    def update_stats(
+        self,
+        filepath: Path | None = None,
+        stats: FileAttributeData | None = None,
+        entry: Entry | None = None,
+    ):
         """Render the panel widgets with the newest data from the Library."""
         if not stats:
             stats = FileAttributeData()
@@ -170,18 +165,15 @@ class FileAttributes(QWidget):
             # Initialize the possible stat variables
             stats_label_text = ""
             ext_display: str = ""
-            file_size: str = ""
+            file_size: str = format_size(entry.file_size) if entry and entry.file_size else ""
             font_family: str = ""
 
             # Attempt to populate the stat variables
             ext_display = ext.upper()[1:] or filepath.stem.upper()
-            if filepath and filepath.is_file():
+            if filepath and filepath.is_file() and MediaTypes.contains("font", ext, SEARCH):
                 try:
-                    file_size = format_size(filepath.stat().st_size)
-
-                    if MediaTypes.contains("font", ext, SEARCH):
-                        font = ImageFont.truetype(filepath)
-                        font_family = f"{font.getname()[0]} ({font.getname()[1]}) "
+                    font = ImageFont.truetype(filepath)
+                    font_family = f"{font.getname()[0]} ({font.getname()[1]}) "
                 except (FileNotFoundError, OSError) as e:
                     logger.error(
                         "[FileAttributes] Could not process file stats", filepath=filepath, error=e
@@ -206,14 +198,15 @@ class FileAttributes(QWidget):
                         f"  •  <span style='color:{orange}'>"
                         f"{Translations['preview.ignored'].upper()}</span>"
                     )
+                if file_size:
+                    stats_label_text += f"  •  {file_size}"
                 if not filepath.exists():
                     stats_label_text = (
                         f"{stats_label_text}"
                         f"  •  <span style='color:{red}'>"
                         f"{Translations['preview.unlinked'].upper()}</span>"
                     )
-                if file_size:
-                    stats_label_text += f"  •  {file_size}"
+
             elif file_size:
                 stats_label_text += file_size
 
diff --git a/src/tagstudio/qt/mixed/fix_unlinked.py b/src/tagstudio/qt/mixed/fix_unlinked.py
index 39cad7c7..4a9a958e 100644
--- a/src/tagstudio/qt/mixed/fix_unlinked.py
+++ b/src/tagstudio/qt/mixed/fix_unlinked.py
@@ -4,12 +4,13 @@
 
 from typing import TYPE_CHECKING, override
 
+import structlog
 from PySide6 import QtCore, QtGui
 from PySide6.QtCore import Qt
 from PySide6.QtWidgets import QHBoxLayout, QLabel, QPushButton, QVBoxLayout, QWidget
 
 from tagstudio.core.library.alchemy.library import Library
-from tagstudio.core.library.alchemy.registries.unlinked_registry import UnlinkedRegistry
+from tagstudio.core.utils.types import unwrap
 from tagstudio.i18n.translations import Translations
 from tagstudio.qt.controllers.merge_dupe_entries_progress import MergeDuplicateEntriesProgress
 from tagstudio.qt.controllers.progress_bar import ProgressWidget
@@ -17,19 +18,19 @@ from tagstudio.qt.controllers.relink_entries_progress import RelinkUnlinkedEntri
 from tagstudio.qt.mixed.remove_unlinked_modal import RemoveUnlinkedEntriesModal
 from tagstudio.qt.views.styles.stylesheets import header
 
-# Only import for type checking/autocompletion, will not be imported at runtime.
 if TYPE_CHECKING:
     from tagstudio.qt.qt_driver import QtDriver
 
+logger = structlog.get_logger(__name__)
 
-# TODO: Split to use MVC guidelines.
+
+# TODO: Split to use MVC guidelines, or completely redo.
 class FixUnlinkedEntriesModal(QWidget):
     def __init__(self, library: Library, driver: QtDriver):
         super().__init__()
         self.lib = library
         self.driver = driver
-
-        self.tracker = UnlinkedRegistry(lib=self.lib)
+        self.sync_engine = driver.sync_engine
 
         self.unlinked_count = -1
         self.dupe_count = -1
@@ -56,14 +57,13 @@ class FixUnlinkedEntriesModal(QWidget):
         self.refresh_unlinked_button.clicked.connect(self.refresh_unlinked)
 
         self.merge_class = MergeDuplicateEntriesProgress(self.lib, self.driver)
-        self.relink_class = RelinkUnlinkedEntriesProgress(self.tracker)
+        self.relink_class = RelinkUnlinkedEntriesProgress(self.sync_engine)
 
         self.search_button = QPushButton(Translations["entries.unlinked.search_and_relink"])
         self.relink_class.done.connect(
-            # refresh the grid
             lambda: (
                 self.driver.update_browsing_state(),
-                self.refresh_unlinked(),
+                self._sync_ui_from_tracker(),
             )
         )
         self.search_button.clicked.connect(self.relink_class.repair_entries)
@@ -72,16 +72,16 @@ class FixUnlinkedEntriesModal(QWidget):
         self.manual_button.setHidden(True)
 
         self.remove_button = QPushButton(Translations["entries.unlinked.remove_alt"])
-        self.remove_modal = RemoveUnlinkedEntriesModal(self.driver, self.tracker)
+        self.remove_modal = RemoveUnlinkedEntriesModal(self.driver, self.sync_engine)
         self.remove_modal.done.connect(
             lambda: (
-                self.set_unlinked_count(),
-                # refresh the grid
                 self.driver.update_browsing_state(),
-                self.refresh_unlinked(),
+                self._sync_ui_from_tracker(),
             )
         )
-        self.remove_button.clicked.connect(self.remove_modal.show)
+        self.remove_button.clicked.connect(
+            lambda: (self.remove_modal.refresh_list(), self.remove_modal.show())
+        )
 
         self.button_container = QWidget()
         self.button_layout = QHBoxLayout(self.button_container)
@@ -106,6 +106,11 @@ class FixUnlinkedEntriesModal(QWidget):
         self.update_unlinked_count()
 
     def refresh_unlinked(self):
+        if self.driver.file_scan_lock:
+            logger.info("[FixUnlinkedEntries] Sync already in progress, ignoring refresh request")
+            return
+        self.driver.file_scan_lock = True
+
         pw = ProgressWidget(
             cancel_button_text=None,
             minimum=0,
@@ -114,37 +119,41 @@ class FixUnlinkedEntriesModal(QWidget):
         pw.setWindowTitle(Translations["library.scan_library.title"])
         pw.update_label(Translations["entries.unlinked.scanning"])
 
-        def update_driver_widgets():
+        def finish():
+            self.driver.file_scan_lock = False
             if (
                 hasattr(self.driver, "library_info_window")
                 and self.driver.library_info_window.isVisible()
             ):
                 self.driver.library_info_window.update_cleanup()
 
+        # Uses the Library's shared path cache
         pw.from_iterable_function(
-            self.tracker.refresh_unlinked_files,
+            lambda: self.sync_engine.sync_dir(unwrap(self.lib.library_dir)),
             None,
             self.set_unlinked_count,
+            finish,
             self.update_unlinked_count,
             self.remove_modal.refresh_list,
-            update_driver_widgets,
         )
 
+    def _sync_ui_from_tracker(self) -> None:
+        """Refresh the UI from the tracker's current state, without rescanning the library."""
+        self.set_unlinked_count()
+        self.update_unlinked_count()
+        self.remove_modal.refresh_list()
+
     def set_unlinked_count(self):
         """Sets the unlinked_entries_count in the Library to the tracker's value."""
-        self.lib.unlinked_entries_count = self.tracker.unlinked_entries_count
+        self.lib.unlinked_entries_count = self.sync_engine.unlinked_entries_count
 
     def update_unlinked_count(self):
         """Updates the UI to reflect the Library's current unlinked_entries_count."""
-        # Indicates that the library is new compared to the last update.
-        # NOTE: Make sure set_unlinked_count() is called before this!
-        if self.tracker.unlinked_entries_count > 0 and self.lib.unlinked_entries_count < 0:
-            self.tracker.reset()
-
         count: int = self.lib.unlinked_entries_count
+        syncing = self.driver.file_scan_lock  # Disabled while a sync is running
 
-        self.search_button.setDisabled(count < 1)
-        self.remove_button.setDisabled(count < 1)
+        self.search_button.setDisabled(count < 1 or syncing)
+        self.remove_button.setDisabled(count < 1 or syncing)
 
         count_text: str = Translations.format(
             "entries.unlinked.unlinked_count", count=count if count >= 0 else "—"
diff --git a/src/tagstudio/qt/mixed/remove_unlinked_modal.py b/src/tagstudio/qt/mixed/remove_unlinked_modal.py
index d34fa02b..38faa86e 100644
--- a/src/tagstudio/qt/mixed/remove_unlinked_modal.py
+++ b/src/tagstudio/qt/mixed/remove_unlinked_modal.py
@@ -9,7 +9,7 @@ from PySide6.QtCore import Qt, QThreadPool, Signal
 from PySide6.QtGui import QStandardItem, QStandardItemModel
 from PySide6.QtWidgets import QHBoxLayout, QLabel, QListView, QPushButton, QVBoxLayout, QWidget
 
-from tagstudio.core.library.alchemy.registries.unlinked_registry import UnlinkedRegistry
+from tagstudio.core.library.sync import LibrarySyncEngine
 from tagstudio.i18n.translations import Translations
 from tagstudio.qt.controllers.progress_bar import ProgressWidget
 from tagstudio.qt.utils.custom_runnable import CustomRunnable
@@ -18,11 +18,11 @@ if TYPE_CHECKING:
     from tagstudio.qt.qt_driver import QtDriver
 
 
-# TODO: Split to use MVC guidelines.
+# TODO: Split to use MVC guidelines or completely redo.
 class RemoveUnlinkedEntriesModal(QWidget):
     done = Signal()
 
-    def __init__(self, driver: QtDriver, tracker: UnlinkedRegistry):
+    def __init__(self, driver: QtDriver, tracker: LibrarySyncEngine):
         super().__init__()
         self.driver = driver
         self.tracker = tracker
diff --git a/src/tagstudio/qt/qt_driver.py b/src/tagstudio/qt/qt_driver.py
index 57ba1877..d38dfb18 100644
--- a/src/tagstudio/qt/qt_driver.py
+++ b/src/tagstudio/qt/qt_driver.py
@@ -17,10 +17,11 @@ import sys
 import time
 from argparse import Namespace
 from collections import OrderedDict
+from collections.abc import Callable, Iterator
 from functools import partial
 from pathlib import Path
 from queue import Queue
-from typing import TypeVar
+from typing import Literal, TypeVar
 from warnings import catch_warnings
 
 import structlog
@@ -47,7 +48,7 @@ from tagstudio.core.library.alchemy.enums import BrowsingState, SortingModeEnum
 from tagstudio.core.library.alchemy.library import Library, LibraryStatus
 from tagstudio.core.library.alchemy.models import Entry
 from tagstudio.core.library.ignore import Ignore
-from tagstudio.core.library.refresh import RefreshTracker
+from tagstudio.core.library.sync import LibrarySyncEngine
 from tagstudio.core.media_types import MediaTypes
 from tagstudio.core.query_lang.file_groups import SEARCH
 from tagstudio.core.query_lang.util import ParsingError
@@ -67,7 +68,6 @@ from tagstudio.qt.controllers.ignore_modal import IgnoreModal
 from tagstudio.qt.controllers.library_info_window import LibraryInfoWindow
 from tagstudio.qt.controllers.main_window import MainWindow
 from tagstudio.qt.controllers.modal import Modal
-from tagstudio.qt.controllers.progress_bar import ProgressWidget
 from tagstudio.qt.controllers.splash import SplashScreen
 from tagstudio.qt.controllers.tag_search_panel import TagSearchPanel
 from tagstudio.qt.controllers.update_available_message_box import UpdateAvailableMessageBox
@@ -104,6 +104,9 @@ else:
     from signal import SIGINT, SIGQUIT, SIGTERM, signal  # pyright: ignore
 
 logger = structlog.get_logger(__name__)
+T = TypeVar("T")
+# Used to track the context state of the banner widget.
+_BannerContext = Literal["new_files", "unlinked", "relinked", "sync_disabled", "sync_finished"]
 
 
 def clamp(value, lower_bound, upper_bound):
@@ -128,9 +131,6 @@ class Consumer(QThread):
                 pass
 
 
-T = TypeVar("T")
-
-
 # Ex. User visits | A ->[B]     |
 #                 | A    B ->[C]|
 #                 | A   [B]<- C |
@@ -192,13 +192,17 @@ class QtDriver(DriverMixin, QObject):
 
     def __init__(self, args: Namespace):
         super().__init__()
-        # prevent recursive badges update when multiple items selected
-        self.badge_update_lock = False
         self.lib = Library()
+        self.sync_engine = LibrarySyncEngine(self.lib)
         self.rm: ResourceManager = ResourceManager()
         self.args = args
         self.frame_content: list[int] = []  # List of Entry IDs for the current query
+        self.badge_update_lock = False
+        self.file_scan_lock: bool = False  # Prevent multiple file scanning operations at once
         self._selected: OrderedDict[int, None] = OrderedDict()
+        self._sync_session_id: int = 0  # Prevent current sync from affecting subsequent libraries.
+        self._sync_disabled_notice_shown: bool = False
+        self._banner_context: _BannerContext | None = None
         self.pages_count = 0
 
         self.scrollbar_pos = 0
@@ -454,9 +458,9 @@ class QtDriver(DriverMixin, QObject):
             set_open_last_loaded_on_startup
         )
 
-        # Refresh Directories
-        self.main_window.menu_bar.refresh_dir_action.triggered.connect(
-            lambda: self.call_if_library_open(self.add_new_files_callback)
+        # Sync Library
+        self.main_window.menu_bar.sync_library_action.triggered.connect(
+            lambda: self.call_if_library_open(self.sync_library_callback)
         )
 
         # Close Library
@@ -552,13 +556,8 @@ class QtDriver(DriverMixin, QObject):
 
         # region Tools Menu ===========================================================
 
-        def create_fix_unlinked_entries_modal():
-            if not hasattr(self, "unlinked_modal"):
-                self.unlinked_modal = FixUnlinkedEntriesModal(self.lib, self)
-            self.unlinked_modal.show()
-
         self.main_window.menu_bar.fix_unlinked_entries_action.triggered.connect(
-            create_fix_unlinked_entries_modal
+            self.open_fix_unlinked_entries_modal
         )
 
         def create_ignored_entries_modal():
@@ -577,7 +576,7 @@ class QtDriver(DriverMixin, QObject):
 
         self.main_window.menu_bar.fix_dupe_files_action.triggered.connect(create_dupe_files_modal)
 
-        # TODO: Move this to a settings screen.
+        # TODO: Make this accessible somewhere more sensible too, like "Library Information"
         self.main_window.menu_bar.clear_thumb_cache_action.triggered.connect(
             lambda: unwrap(self.cache_manager).clear_cache()
         )
@@ -638,6 +637,7 @@ class QtDriver(DriverMixin, QObject):
         self.init_library_window()
         self.migration_modal: JsonMigrationModal | None = None
 
+        self.main_window.banner.request_extra_duration()
         path_result = self.evaluate_path(str(self.args.open).lstrip().rstrip())
         if path_result.success and path_result.library_path:
             self.open_library(path_result.library_path)
@@ -678,6 +678,9 @@ class QtDriver(DriverMixin, QObject):
         # adj_font_size = math.floor(12 * self.main_window.devicePixelRatio())
 
         def _update_browsing_state():
+            # Clear any banner asking for a manual refresh of the view
+            if self._banner_context == "new_files":
+                self._clear_notice()
             try:
                 self.update_browsing_state(
                     BrowsingState.from_search_query(self.main_window.search_field.text())
@@ -725,9 +728,11 @@ class QtDriver(DriverMixin, QObject):
         self.main_window.back_button.clicked.connect(lambda: self.navigation_callback(-1))
         self.main_window.forward_button.clicked.connect(lambda: self.navigation_callback(1))
 
-        # NOTE: Putting this early will result in a white non-responsive
-        # window until everything is loaded. Consider adding a splash screen
-        # or implementing some clever loading tricks.
+        # Banner
+        self.main_window.banner.notice_action_clicked.connect(self._on_notice_action_clicked)
+        self.main_window.banner.cancel_requested.connect(self._on_sync_cancel_requested)
+
+        # NOTE: Putting this too early will result in a non-responsive white window on start.
         self.main_window.show()
         self.main_window.activateWindow()
         self.main_window.toggle_landing_page(enabled=True)
@@ -784,8 +789,14 @@ class QtDriver(DriverMixin, QObject):
         if not self.lib.library_dir:
             logger.info("No Library to Close")
             return
-
         logger.info("Closing Library...")
+
+        self.sync_engine.cancelled = True
+        self.file_scan_lock = False
+        self._new_sync_session()  # Invalidate any sync still active for the old library
+        self._banner_context = None
+        self.main_window.banner.hide_banner(force=True)
+
         self.main_window.status_bar.showMessage(Translations["status.library_closing"])
         start_time = time.time()
 
@@ -800,6 +811,7 @@ class QtDriver(DriverMixin, QObject):
         self.__reset_navigation()
 
         self.lib.close()
+        self.sync_engine.reset()
         self.cache_manager = None
 
         self.thumb_job_queue.queue.clear()
@@ -827,7 +839,7 @@ class QtDriver(DriverMixin, QObject):
         try:
             self.main_window.menu_bar.save_library_backup_action.setEnabled(False)
             self.main_window.menu_bar.close_library_action.setEnabled(False)
-            self.main_window.menu_bar.refresh_dir_action.setEnabled(False)
+            self.main_window.menu_bar.sync_library_action.setEnabled(False)
             self.main_window.menu_bar.tag_manager_action.setEnabled(False)
             self.main_window.menu_bar.color_manager_action.setEnabled(False)
             self.main_window.menu_bar.field_template_manager_action.setEnabled(False)
@@ -1067,82 +1079,269 @@ class QtDriver(DriverMixin, QObject):
 
         return msg.exec()
 
-    def add_new_files_callback(self):
-        """Run when user initiates adding new files to the Library."""
-        tracker = RefreshTracker(self.lib)
+    def _run_sync_step(
+        self,
+        generator: Callable[[], Iterator[T]],
+        on_progress: Callable[[T], None],
+        on_done: Callable[[], None],
+    ) -> None:
+        """Run a generator function on a background thread with signals for progress and completion.
 
-        pw = ProgressWidget(
-            cancel_button_text=None,
-            minimum=0,
-            maximum=0,
+        Args:
+            generator (Callable[[], Iterator[T]]): Zero-argument callable returning the
+                generator to iterate.
+            on_progress (Callable[[T], None]): Called on the main thread with each yielded value.
+            on_done (Callable[[], None]): Called on the main thread once `generator` is finished.
+        """
+        iterator = FunctionIterator(generator)
+        iterator.value.connect(on_progress)
+        runnable = CustomRunnable(iterator.run)
+        runnable.done.connect(on_done)
+        QThreadPool.globalInstance().start(runnable)
+
+    def sync_library_callback(self):
+        """Run when syncing a Library is initiated."""
+        if self.file_scan_lock:
+            logger.info("[QtDriver] Sync already in progress, ignoring request")
+            return
+        self.file_scan_lock = True
+        session_id = self._new_sync_session()
+        # Disable the "Fix Unlinked Entries" modal's relink/remove actions during the sync
+        if hasattr(self, "unlinked_modal") and self.unlinked_modal.isVisible():
+            self.unlinked_modal.update_unlinked_count()
+
+        engine = self.sync_engine
+        library_dir = unwrap(self.lib.library_dir)
+        self.main_window.banner.show_progress(
+            Translations["library.sync.preparing"], phase="preparing"
         )
-        pw.setWindowTitle(Translations["library.refresh.title"])
-        pw.update_label(Translations["library.refresh.scanning_preparing"])
-        pw.show()
 
-        iterator = FunctionIterator(lambda lib=self.lib.library_dir: tracker.refresh_dir(lib))
-        iterator.value.connect(
-            lambda x: (
-                pw.update_progress(x + 1),
-                pw.update_label(
-                    Translations.format(
-                        "library.refresh.scanning.plural"
-                        if x + 1 != 1
-                        else "library.refresh.scanning.singular",
-                        searched_count=f"{x + 1:n}",
-                        found_count=f"{tracker.files_count:n}",
-                    )
+        def on_progress(progress: tuple[int, int]) -> None:
+            if engine.cancelled:
+                return
+            searched_count, found_count = progress
+            self.main_window.banner.show_progress(
+                Translations.format(
+                    "library.sync.scanning",
+                    searched_count=f"{searched_count + 1:n}",
+                    found_count=f"{found_count:n}",
                 ),
+                phase="scanning",
             )
-        )
-        r = CustomRunnable(iterator.run)
-        r.done.connect(
-            lambda: (
-                pw.hide(),
-                pw.deleteLater(),
-                self.add_new_files_runnable(tracker),
-            )
-        )
-        QThreadPool.globalInstance().start(r)
 
-    def add_new_files_runnable(self, tracker: RefreshTracker):
+        def _start_scan() -> None:
+            self._run_sync_step(
+                lambda lib=library_dir: engine.sync_dir(lib),
+                on_progress,
+                lambda: self.save_new_entries_runnable(engine, session_id=session_id),
+            )
+
+        self.main_window.banner.call_when_open(_start_scan)
+
+    def _finish_sync(
+        self,
+        new_count: int = 0,
+        unlinked_count: int = 0,
+        relinked_count: int = 0,
+        session_id: int = 0,
+    ):
+        """Reset the banner once the sync is completed.
+
+        Args:
+            new_count (int): New files count.
+            unlinked_count (int): Unlinked entries count.
+            relinked_count (int): Automatically relinked files count.
+            session_id (int): The sync_session_id this sync started with.
+        """
+        if self._is_sync_stale(session_id):
+            return
+
+        self.file_scan_lock = False
+        self.lib.unlinked_entries_count = unlinked_count
+        if hasattr(self, "unlinked_modal") and self.unlinked_modal.isVisible():
+            self.unlinked_modal.update_unlinked_count()
+
+        if self.sync_engine.cancelled:
+            return
+
+        # Show fleeting count of any new files added with button to refresh view
+        if new_count:
+            text = Translations.format(
+                "library.sync.new_files_banner.plural"
+                if new_count != 1
+                else "library.sync.new_files_banner.singular",
+                count=f"{new_count:n}",
+            )
+            text += self._count_suffix(relinked_count, "library.sync.relinked_suffix")
+            if relinked_count:
+                text += self._count_suffix(unlinked_count, "library.sync.remaining_unlinked_suffix")
+            self._show_notice("new_files", text, Translations["entries.generic.refresh_alt"])
+        # Show persistent count of any remaining unlinked files and button to manually review
+        elif unlinked_count:
+            text = Translations.format(
+                "library.sync.unlinked_banner.plural"
+                if unlinked_count != 1
+                else "library.sync.unlinked_banner.singular",
+                count=f"{unlinked_count:n}",
+            )
+            text += self._count_suffix(relinked_count, "library.sync.relinked_suffix")
+            self._show_notice("unlinked", text, Translations["entries.unlinked.review"])
+        # Show fleeting notice number of entries automatically relinked
+        elif relinked_count:
+            text = Translations.format(
+                "library.sync.relinked_banner.plural"
+                if relinked_count != 1
+                else "library.sync.relinked_banner.singular",
+                count=f"{relinked_count:n}",
+            )
+            text += self._count_suffix(unlinked_count, "library.sync.remaining_unlinked_suffix")
+            self._show_notice("relinked", text, Translations["entries.generic.refresh_alt"])
+        # Show a fleeting "Library Synced" message
+        else:
+            self._show_notice("sync_finished", Translations["library.sync.complete"])
+
+    def _count_suffix(self, count: int, key: str) -> str:
+        """Build a count suffix suffix, or "" if count is 0."""
+        if not count:
+            return ""
+        return " " + Translations.format(key, count=f"{count:n}")
+
+    def _new_sync_session(self) -> int:
+        """Increment the sync session, invalidating any active sync's callbacks."""
+        self._sync_session_id += 1
+        return self._sync_session_id
+
+    def _is_sync_stale(self, session_id: int) -> bool:
+        """Whether `session_id` belongs to an older sync session and should be invalidated."""
+        return session_id != self._sync_session_id
+
+    def _show_notice(
+        self, context: _BannerContext, message: str, button_text: str | None = None
+    ) -> None:
+        """Show a "notice" banner and keep track of its context type.
+
+        Args:
+            context (_BannerContext): The subtype of banner notice.
+                Used to keep track of the context state currently used for the banner.
+                This could be for a startup message, sync progress, an entry relink prompt, etc.
+            message (str): The notice message text.
+            button_text (str): The action button text.
+        """
+        self._banner_context = context
+        if button_text is not None:
+            self.main_window.banner.show_notice(message, button_text)
+        else:
+            self.main_window.banner.show_fleeting_notice(message)
+
+    def _clear_notice(self, force: bool = False) -> None:
+        self._banner_context = None
+        self.main_window.banner.hide_banner(force=force)
+
+    def _on_notice_action_clicked(self) -> None:
+        if self._banner_context == "unlinked":
+            self._on_unlinked_banner_review()
+        elif self._banner_context == "sync_disabled":
+            self._on_sync_disabled_open_settings()
+        else:  # "new_files" or "relinked"
+            self._on_new_files_banner_refresh()
+
+    def _on_new_files_banner_refresh(self):
+        self.update_browsing_state()
+        # If there are still unlinked entries after the automatic relinking step, show a notice.
+        if self.lib.unlinked_entries_count > 0:
+            count = self.lib.unlinked_entries_count
+            text = Translations.format(
+                "library.sync.unlinked_banner.plural"
+                if count != 1
+                else "library.sync.unlinked_banner.singular",
+                count=f"{count:n}",
+            )
+            self._show_notice("unlinked", text, Translations["entries.unlinked.review"])
+        else:
+            self._clear_notice(force=True)
+
+    def _on_unlinked_banner_review(self):
+        self._clear_notice(force=True)
+        self.open_fix_unlinked_entries_modal()
+
+    def _on_sync_disabled_open_settings(self):
+        self._clear_notice(force=True)
+        self.open_settings_modal()
+
+    def _on_sync_cancel_requested(self):
+        """Stop the in-progress sync at its next opportunity."""
+        self.sync_engine.cancelled = True
+        logger.info("[QtDriver] Sync cancelled")
+
+    def open_fix_unlinked_entries_modal(self):
+        if not hasattr(self, "unlinked_modal"):
+            self.unlinked_modal = FixUnlinkedEntriesModal(self.lib, self)
+        self.unlinked_modal.show()
+
+    def sync_entry_stats_runnable(
+        self,
+        engine: LibrarySyncEngine,
+        new_count: int = 0,
+        unlinked_count: int = 0,
+        relinked_count: int = 0,
+        session_id: int = 0,
+    ):
+        """Refresh cached stat() data for files already known to the library.
+
+        Threaded method.
+        """
+        if self._is_sync_stale(session_id):
+            return
+        restat_count = engine.restat_count
+
+        def on_progress(idx: int) -> None:
+            if engine.cancelled:
+                return
+            self.main_window.banner.show_progress(
+                Translations.format(
+                    "library.sync.updating.label", idx=f"{idx:n}", total=f"{restat_count:n}"
+                ),
+                idx,
+                restat_count,
+                phase="updating",
+            )
+
+        on_progress(0)
+        self._run_sync_step(
+            engine.sync_entry_stats,
+            on_progress,
+            lambda: self._finish_sync(new_count, unlinked_count, relinked_count, session_id),
+        )
+
+    def save_new_entries_runnable(self, engine: LibrarySyncEngine, session_id: int = 0):
         """Adds any known new files to the library and run default macros on them.
 
         Threaded method.
         """
-        files_count = tracker.files_count
+        if self._is_sync_stale(session_id):
+            return
+        new_count = engine.new_file_count
+        unlinked_count = engine.unlinked_entries_count
+        relinked_count = engine.relinked_entries_count
 
-        iterator = FunctionIterator(tracker.save_new_files)
-        pw = ProgressWidget(
-            cancel_button_text=None,
-            minimum=0,
-            maximum=0,
-        )
-        pw.setWindowTitle(Translations["entries.running.dialog.title"])
-        pw.update_label(
-            Translations.format("entries.running.dialog.new_entries", total=f"{files_count:n}")
-        )
-        pw.show()
+        def on_progress(idx: int) -> None:
+            if engine.cancelled:
+                return
+            self.main_window.banner.show_progress(
+                Translations.format("entries.running.dialog.new_entries", total=f"{new_count:n}"),
+                idx,
+                new_count,
+                phase="new_entries",
+            )
 
-        iterator.value.connect(
-            lambda _count: (
-                pw.update_label(
-                    Translations.format(
-                        "entries.running.dialog.new_entries", total=f"{files_count:n}"
-                    )
-                ),
-            )
+        on_progress(0)
+        self._run_sync_step(
+            engine.save_new_entries,
+            on_progress,
+            lambda: self.sync_entry_stats_runnable(
+                engine, new_count, unlinked_count, relinked_count, session_id
+            ),
         )
-        r = CustomRunnable(iterator.run)
-        r.done.connect(
-            lambda: (
-                pw.hide(),
-                pw.deleteLater(),
-                # refresh the library only when new items are added
-                files_count and self.update_browsing_state(),
-            )
-        )
-        QThreadPool.globalInstance().start(r)
 
     def new_file_macros_runnable(self, new_ids):
         """Threaded method that runs macros on a set of Entry IDs."""
@@ -1640,7 +1839,7 @@ class QtDriver(DriverMixin, QObject):
             f"[Config] Thumbnail Cache Size: {format_size(cache_size)}",
         )
 
-        # Migration is required
+        # JSON Migration is required
         if open_status.json_migration_req:
             self.migration_modal = JsonMigrationModal(path)
             self.migration_modal.migration_finished.connect(
@@ -1666,7 +1865,19 @@ class QtDriver(DriverMixin, QObject):
         self.__reset_navigation()
 
         if self.settings.scan_files_on_open:
-            self.add_new_files_callback()
+            self.sync_library_callback()
+        elif not self._sync_disabled_notice_shown:
+            self._sync_disabled_notice_shown = True
+            # Show that the setting for opening a library on start is turned off,
+            # with a prompt to open the settings to change that (encouraged but not required).
+            self._show_notice(
+                "sync_disabled",
+                Translations.format(
+                    "library.sync.disabled_notice",
+                    sync_setting=Translations["settings.scan_files_on_open"],
+                ),
+                Translations["library.sync.open_settings"],
+            )
 
         if self.settings.show_filepath == ShowFilepathOption.SHOW_FULL_PATHS:
             library_dir_display = self.lib.library_dir
@@ -1688,7 +1899,7 @@ class QtDriver(DriverMixin, QObject):
         self.set_select_actions_visibility()
         self.main_window.menu_bar.save_library_backup_action.setEnabled(True)
         self.main_window.menu_bar.close_library_action.setEnabled(True)
-        self.main_window.menu_bar.refresh_dir_action.setEnabled(True)
+        self.main_window.menu_bar.sync_library_action.setEnabled(True)
         self.main_window.menu_bar.tag_manager_action.setEnabled(True)
         self.main_window.menu_bar.color_manager_action.setEnabled(True)
         self.main_window.menu_bar.field_template_manager_action.setEnabled(True)
diff --git a/src/tagstudio/qt/views/banner_view.py b/src/tagstudio/qt/views/banner_view.py
new file mode 100644
index 00000000..aff8003b
--- /dev/null
+++ b/src/tagstudio/qt/views/banner_view.py
@@ -0,0 +1,47 @@
+# SPDX-FileCopyrightText: (c) TagStudio Contributors
+# SPDX-License-Identifier: GPL-3.0-only
+
+
+from PySide6.QtWidgets import QHBoxLayout, QPushButton, QVBoxLayout
+
+from tagstudio.i18n.translations import Translations
+from tagstudio.qt.controllers.rounded_progress_bar import RoundedProgressBar
+from tagstudio.qt.controllers.stable_label import StableLabel
+
+
+class BannerView(QVBoxLayout):
+    PROGRESS_BAR_HEIGHT = 4
+
+    def __init__(self) -> None:
+        super().__init__()
+        self.setContentsMargins(0, 0, 0, 0)
+        self.setSpacing(0)
+
+        content_row = QHBoxLayout()
+        content_row.setContentsMargins(6, 6, 6, 2)
+        content_row.setSpacing(8)
+
+        self.close_button = QPushButton("×")
+        self.close_button.setObjectName("bannerCloseButton")
+        self.close_button.setFixedSize(24, 24)
+        content_row.addWidget(self.close_button)
+
+        content_row.addStretch(1)
+
+        self.label = StableLabel()
+        content_row.addWidget(self.label)
+
+        self.action_button = QPushButton(Translations["entries.generic.refresh_alt"])
+        self.action_button.setObjectName("bannerActionButton")
+        content_row.addWidget(self.action_button)
+
+        content_row.addStretch(1)
+        self.addLayout(content_row, 1)
+
+        self.progress_bar = RoundedProgressBar()
+        self.progress_bar.setFixedHeight(self.PROGRESS_BAR_HEIGHT)
+
+        policy = self.progress_bar.sizePolicy()
+        policy.setRetainSizeWhenHidden(True)
+        self.progress_bar.setSizePolicy(policy)
+        self.addWidget(self.progress_bar)
diff --git a/src/tagstudio/qt/views/layouts/thumb_grid_layout.py b/src/tagstudio/qt/views/layouts/thumb_grid_layout.py
index a7c3e8dc..dc1f6919 100644
--- a/src/tagstudio/qt/views/layouts/thumb_grid_layout.py
+++ b/src/tagstudio/qt/views/layouts/thumb_grid_layout.py
@@ -57,8 +57,6 @@ class ThumbGridLayout(QLayout):
         self._scroll_to = entry_id
 
     def set_entries(self, entry_ids: list[int]):
-        self.scroll_area.verticalScrollBar().setValue(0)
-
         self._entry_ids = entry_ids
         self._entries.clear()
         self._tag_entries.clear()
@@ -211,9 +209,10 @@ class ThumbGridLayout(QLayout):
                 pass
             self._scroll_to = None
 
-        visible_rows = math.ceil((view_height + (offset % height_offset)) / height_offset)
-        offset = int(offset / height_offset)
-        start = offset * per_row
+        row_offset = offset
+        visible_rows = math.ceil((view_height + (row_offset % height_offset)) / height_offset)
+        row_offset = int(row_offset / height_offset)
+        start = row_offset * per_row
         end = start + (visible_rows * per_row)
 
         first_visible = self._entry_ids[start] if 0 <= start < len(self._entry_ids) else None
diff --git a/src/tagstudio/qt/views/styles/stylesheets.py b/src/tagstudio/qt/views/styles/stylesheets.py
index 69d1b085..417b795b 100644
--- a/src/tagstudio/qt/views/styles/stylesheets.py
+++ b/src/tagstudio/qt/views/styles/stylesheets.py
@@ -19,6 +19,9 @@ from tagstudio.qt.views.styles.palette import (
 # TODO: There's plenty of good opportunities here to consolidate similar styles.
 # Work should be done to more closely use Qt's theming systems rather than override them.
 
+# Shared with RoundedProgressBar.set_corner_radius() so both use the exact same corner arc.
+BANNER_CORNER_RADIUS = 6
+
 
 def add_button_style() -> str:
     """Style used for tag-like "Add" buttons [+]."""
@@ -557,6 +560,142 @@ def preview_warning_style() -> str:
     """
 
 
+def _is_dark_theme() -> bool:
+    return QGuiApplication.styleHints().colorScheme() is Qt.ColorScheme.Dark
+
+
+def get_contrast_text_color(background_color: QColor) -> QColor:
+    """Return plain black or white, whichever reads better against `background_color`."""
+    return QColor(0, 0, 0) if background_color.lightness() > 120 else QColor(255, 255, 255)
+
+
+def _banner_button_hover_style(object_name: str) -> str:
+    """Shared hover/pressed/focus feedback for the banner's accent-tinted buttons."""
+    hover = Palette.accent().darker(140)
+    pressed = Palette.accent().lighter(120)
+    return f"""
+    QPushButton#{object_name}::hover {{
+        background-color: rgba{hover.toTuple()};
+    }}
+    QPushButton#{object_name}::pressed {{
+        background-color: rgba{pressed.toTuple()};
+    }}
+    QPushButton#{object_name}::focus {{
+        outline: none;
+    }}
+    """
+
+
+def banner_close_button_style() -> str:
+    """Style for the banner's close ("X") button in accent-colored notice modes."""
+    accent = Palette.accent().darker(180)
+    text_color = get_contrast_text_color(accent)
+
+    return f"""
+    QPushButton#bannerCloseButton {{
+        font-size: 24pt;
+        padding-bottom: 4px;
+        background: transparent;
+        color: rgba{text_color.toTuple()};
+        border: none;
+        border-radius: 3px;
+    }}
+    {_banner_button_hover_style("bannerCloseButton")}
+    """
+
+
+def banner_action_button_style() -> str:
+    """Style for the banner's action button (Refresh / Review / Open Settings)."""
+    accent = Palette.accent().darker(160)
+    text_color = get_contrast_text_color(accent)
+
+    return f"""
+    QPushButton#bannerActionButton {{
+        background-color: rgba{accent.toTuple()};
+        color: rgba{text_color.toTuple()};
+        border: none;
+        border-radius: 3px;
+        padding: 4px 8px;
+        outline: none;
+    }}
+    {_banner_button_hover_style("bannerActionButton")}
+    """
+
+
+def banner_notice_bg_color() -> QColor:
+    """Fill color for the banner card in "notice" mode."""
+    color = QColor(Palette.accent())
+    color.setAlpha(235)
+    return color
+
+
+def banner_notice_style() -> str:
+    """Label/button rules for the banner's accent-colored "notice" mode."""
+    accent = Palette.accent()
+    text_color = get_contrast_text_color(accent)
+
+    return f"""
+    #banner QLabel {{ color: rgba{text_color.toTuple()}; background: transparent; }}
+    {banner_close_button_style()}
+    {banner_action_button_style()}
+    """
+
+
+def banner_close_button_progress_style() -> str:
+    """Close button style for the progress banner mode."""
+    is_dark = _is_dark_theme()
+    text_color = QColor(255, 255, 255) if is_dark else QColor(0, 0, 0)
+    hover = "rgba(255, 255, 255, 40)" if is_dark else "rgba(0, 0, 0, 40)"
+    pressed = "rgba(255, 255, 255, 70)" if is_dark else "rgba(0, 0, 0, 70)"
+
+    return f"""
+    QPushButton#bannerCloseButton {{
+        font-size: 24pt;
+        padding-bottom: 4px;
+        background: transparent;
+        color: rgba{text_color.toTuple()};
+        border: none;
+        border-radius: 3px;
+    }}
+    QPushButton#bannerCloseButton::hover {{
+        background-color: {hover};
+    }}
+    QPushButton#bannerCloseButton::pressed {{
+        background-color: {pressed};
+    }}
+    QPushButton#bannerCloseButton::focus {{
+        outline: none;
+    }}
+    """
+
+
+def banner_progress_bg_color() -> QColor:
+    """Fill color for the banner card in "progress"/"fleeting_notice" mode."""
+    is_dark = _is_dark_theme()
+    return QColor(
+        ThemePalette.COLOR_BG_DARK.value if is_dark else ThemePalette.COLOR_BG_LIGHT.value
+    )
+
+
+def banner_progress_style() -> str:
+    """Label/button rules for the banner's neutral "progress" mode."""
+    is_dark = _is_dark_theme()
+    text_str = "white" if is_dark else "black"
+
+    return f"""
+    #banner QLabel {{ color: {text_str}; background: transparent; }}
+    {banner_close_button_progress_style()}
+    """
+
+
+def banner_progress_chunk_color() -> QColor:
+    """Fill color for the banner's custom-painted progress bar chunk."""
+    is_dark = _is_dark_theme()
+    chunk = QColor(Palette.accent().lighter(130) if is_dark else Palette.accent().darker(115))
+    chunk.setAlpha(235)
+    return chunk
+
+
 def header(string: str, level: int, color: str | None = None) -> str:
     """Wrap a string in HTML header tags.
 
diff --git a/src/tagstudio/resources/translations/en.json b/src/tagstudio/resources/translations/en.json
index 5f35ae38..cd8915dc 100644
--- a/src/tagstudio/resources/translations/en.json
+++ b/src/tagstudio/resources/translations/en.json
@@ -3,13 +3,13 @@
     "about.config_path": "Config Path",
     "about.description": "TagStudio is a photo and file organization application with an underlying tag-based system that focuses on giving freedom and flexibility to the user. No proprietary programs or formats, no sea of sidecar files, and no complete upheaval of your filesystem structure.",
     "about.documentation": "Documentation",
+    "about.library_version": "Library Format",
     "about.module.found": "Found",
     "about.modules.title": "Optional Modules",
     "about.title": "About TagStudio",
     "about.version": "Version",
     "about.version.latest": "{built_version} (Latest Release: {latest_version})",
     "about.website": "Website",
-    "about.library_version": "Library Format",
     "app.git": "Git Commit",
     "app.nightly": "Nightly",
     "app.pre_release": "Pre-Release",
@@ -62,7 +62,6 @@
     "entries.remove.plural.confirm": "Are you sure you want to remove these <b>{count}</b> entries from your library? No files on disk will be deleted.",
     "entries.remove.singular.confirm": "Are you sure you want to remove this entry from your library? No files on disk will be deleted.",
     "entries.running.dialog.new_entries": "Adding {total} New File Entries…",
-    "entries.running.dialog.title": "Adding New File Entries",
     "entries.tags": "Tags",
     "entries.unlinked.description": "Each library entry is linked to a file in one of your directories. If a file linked to an entry is moved or deleted outside of TagStudio, it is then considered unlinked.<br><br>Unlinked entries may be automatically relinked via searching your directories or deleted if desired.",
     "entries.unlinked.relink.attempting": "Attempting to Relink {index}/{unlinked_count} Entries, {fixed_count} Successfully Relinked",
@@ -70,6 +69,7 @@
     "entries.unlinked.relink.title": "Relinking Entries",
     "entries.unlinked.remove": "Remove Unlinked Entries",
     "entries.unlinked.remove_alt": "Remo&ve Unlinked Entries",
+    "entries.unlinked.review": "Manual &Review",
     "entries.unlinked.scanning": "Scanning Library for Unlinked Entries…",
     "entries.unlinked.search_and_relink": "&Search && Relink",
     "entries.unlinked.title": "Fix Unlinked Entries",
@@ -121,6 +121,7 @@
     "file.open_location.mac": "Reveal in Finder",
     "file.open_location.windows": "Show in File Explorer",
     "file.path": "File Path",
+    "file.size": "File Size",
     "folders_to_tags.close_all": "Close All",
     "folders_to_tags.converting": "Converting folders to Tags",
     "folders_to_tags.description": "Creates tags based on your folder structure and applies them to your entries.\n The structure below shows all the tags that will be created and what entries they will be applied to.",
@@ -253,11 +254,21 @@
     "library_object.slug_required": "ID Slug (Required)",
     "library.missing": "Library Location is Missing",
     "library.name": "Library",
-    "library.refresh.scanning_preparing": "Scanning Directories for New Files…\nPreparing…",
-    "library.refresh.scanning.plural": "Scanning Directories for New Files…\n{searched_count} Files Searched, {found_count} New Files Found",
-    "library.refresh.scanning.singular": "Scanning Directories for New Files…\n{searched_count} File Searched, {found_count} New Files Found",
-    "library.refresh.title": "Refreshing Directories",
     "library.scan_library.title": "Scanning Library",
+    "library.sync.complete": "Library Synced",
+    "library.sync.disabled_notice": "\"{sync_setting}\" Is Currently Turned Off",
+    "library.sync.new_files_banner.plural": "{count} New Files Found",
+    "library.sync.new_files_banner.singular": "{count} New File Found",
+    "library.sync.open_settings": "Open &Settings",
+    "library.sync.preparing": "Preparing to Sync…",
+    "library.sync.relinked_banner.plural": "{count} Files Automatically Relinked",
+    "library.sync.relinked_banner.singular": "{count} File Automatically Relinked",
+    "library.sync.relinked_suffix": "({count} Automatically Relinked)",
+    "library.sync.remaining_unlinked_suffix": "({count} Still Unlinked)",
+    "library.sync.scanning": "Discovering Files… ({found_count} New Out of {searched_count})",
+    "library.sync.unlinked_banner.plural": "{count} Unlinked Entries Found",
+    "library.sync.unlinked_banner.singular": "{count} Unlinked Entry Found",
+    "library.sync.updating.label": "Syncing {idx}/{total} Entries…",
     "macros.running.dialog.new_entries": "Running Configured Macros on {count}/{total} New File Entries…",
     "macros.running.dialog.title": "Running Macros on New Entries",
     "media_player.autoplay": "Autoplay",
@@ -280,9 +291,9 @@
     "menu.file.open_create_library": "&Open/Create Library",
     "menu.file.open_library": "Open Library",
     "menu.file.open_recent_library": "Open Recent",
-    "menu.file.refresh_directories": "&Refresh Directories",
     "menu.file.save_backup": "&Save Library Backup",
     "menu.file.save_library": "Save Library",
+    "menu.file.sync_library": "&Sync Library",
     "menu.help": "&Help",
     "menu.help.about": "About",
     "menu.macros": "&Macros",
@@ -335,10 +346,10 @@
     "settings.library": "Library Settings",
     "settings.localization": "Localization",
     "settings.media": "Media",
-    "settings.open_library_on_start": "Open Library on Start",
+    "settings.open_library_on_start": "Open Last Library on Start",
     "settings.page_size": "Page Size",
     "settings.restart_required": "Please restart TagStudio for changes to take effect.",
-    "settings.scan_files_on_open": "Automatically Load New Files",
+    "settings.scan_files_on_open": "Sync Library on Open",
     "settings.show_filenames_in_grid": "Show Filenames in Grid",
     "settings.show_recent_libraries": "Show Recent Libraries",
     "settings.splash.label": "Splash Screen",
diff --git a/tests/core/library/test_library.py b/tests/core/library/test_library.py
index 2ee25f64..a89cb9fb 100644
--- a/tests/core/library/test_library.py
+++ b/tests/core/library/test_library.py
@@ -9,7 +9,7 @@ from tempfile import TemporaryDirectory
 import pytest
 import structlog
 
-from tagstudio.core.library.alchemy.enums import BrowsingState
+from tagstudio.core.library.alchemy.enums import BrowsingState, SortingModeEnum
 from tagstudio.core.library.alchemy.fields import (
     DatetimeField,
     TextField,
@@ -80,11 +80,52 @@ def test_library_add_file(library: Library):
         fields=[TextField(name="Title", value="I'm a Test Title")],
     )
 
-    assert not library.get_entry_id_from_path(entry.path)
+    assert library.get_entry_id_from_path(entry.path) == -1
     assert library.add_entries([entry])
     assert library.get_entry_id_from_path(entry.path)
 
 
+def test_path_cache_untouched_when_not_yet_built(library: Library):
+    """Only `get_or_build_path_cache()` may build the path cache."""
+    assert library.path_cache is None
+    entry = Entry(path=Path("before_any_cache.txt"), fields=[])
+    library.add_entries([entry])
+    assert library.path_cache is None
+
+
+def test_path_cache_self_maintained_by_add_entries(library: Library):
+    """`add_entries()` must keep an already-built path cache up to date on its own."""
+    library.is_case_sensitive_fs = True
+    cache = library.get_or_build_path_cache()
+    assert Path("added_directly.txt") not in cache
+
+    entry = Entry(path=Path("added_directly.txt"), fields=[])
+    new_ids = library.add_entries([entry])
+    assert cache.get(Path("added_directly.txt")) == new_ids[0]
+
+
+def test_path_cache_self_maintained_by_remove_entries(library: Library):
+    library.is_case_sensitive_fs = True
+    cache = library.get_or_build_path_cache()
+    entry = Entry(path=Path("to_remove.txt"), fields=[])
+    entry_id = library.add_entries([entry])[0]
+    assert cache.get(Path("to_remove.txt")) == entry_id
+
+    library.remove_entries([entry_id])
+    assert Path("to_remove.txt") not in cache
+
+
+def test_path_cache_self_maintained_by_update_entry_path(library: Library):
+    library.is_case_sensitive_fs = True
+    cache = library.get_or_build_path_cache()
+    entry = Entry(path=Path("old_location.txt"), fields=[])
+    entry_id = library.add_entries([entry])[0]
+
+    assert library.update_entry_path(entry_id, Path("new_location.txt"))
+    assert Path("old_location.txt") not in cache
+    assert cache.get(Path("new_location.txt")) == entry_id
+
+
 def test_create_tag(library: Library, generate_tag: Callable[..., Tag]):
     # tag already exists
     assert library.add_tag(generate_tag("foo", id=1000)) is None
@@ -148,6 +189,35 @@ def test_entries_count(library: Library):
     assert len(results) == 5
 
 
+@pytest.mark.parametrize(
+    "sorting_mode",
+    [SortingModeEnum.DATE_CREATED, SortingModeEnum.DATE_MODIFIED, SortingModeEnum.FILE_SIZE],
+)
+def test_search_library_sorting(library: Library, sorting_mode: SortingModeEnum):
+    entries = [
+        Entry(
+            path=Path(f"sort_{i}.txt"),
+            fields=[],
+            date_created=float(i),
+            date_modified=float(i),
+            file_size=i,
+        )
+        for i in range(3)
+    ]
+    new_ids = library.add_entries(entries)
+    assert len(new_ids) == 3
+
+    results = library.search_library(
+        BrowsingState.show_all()
+        .with_sorting_mode(sorting_mode)
+        .with_sorting_direction(ascending=True),
+        page_size=None,
+    )
+
+    sorted_new_ids = [entry_id for entry_id in results if entry_id in new_ids]
+    assert sorted_new_ids == new_ids
+
+
 def test_parents_add(library: Library, generate_tag: Callable[..., Tag]):
     # Given
     tag: Tag = library.tags[0]
@@ -338,7 +408,7 @@ def test_merge_entries(library: Library):
     entry_b_: Entry = unwrap(library.get_entry_full(entry_b_id))
 
     assert library.merge_entries(entry_a_, entry_b_)
-    assert not library.get_entry_id_from_path(Path("a"))
+    assert library.get_entry_id_from_path(Path("a")) == -1
     assert library.get_entry_id_from_path(Path("b"))
 
     entry_b_merged = unwrap(library.get_entry_full(entry_b_id))
diff --git a/tests/core/library/test_refresh.py b/tests/core/library/test_refresh.py
deleted file mode 100644
index 01578aad..00000000
--- a/tests/core/library/test_refresh.py
+++ /dev/null
@@ -1,50 +0,0 @@
-# SPDX-FileCopyrightText: (c) TagStudio Contributors
-# SPDX-License-Identifier: GPL-3.0-only
-
-
-from pathlib import Path
-from tempfile import TemporaryDirectory
-
-import pytest
-
-from tagstudio.core.constants import IGNORE_NAME
-from tagstudio.core.library.alchemy.library import Library
-from tagstudio.core.library.refresh import RefreshTracker
-from tagstudio.core.utils.types import unwrap
-
-CWD = Path(__file__).parent
-
-
-@pytest.mark.parametrize("exclude_mode", [True, False])
-@pytest.mark.parametrize("library", [TemporaryDirectory()], indirect=True)
-def test_refresh_new_files(library: Library, exclude_mode: bool):
-    library_dir = unwrap(library.library_dir)
-    # Given
-    registry = RefreshTracker(library=library)
-    library.included_files.clear()
-    (library_dir / "FOO.MD").touch()
-    (library_dir / IGNORE_NAME).write_text("*.md" if exclude_mode else "*\n!*.md")
-
-    # Test if the single file was added
-    list(registry.refresh_dir(library_dir, force_internal_tools=True))
-    assert set(registry.files_not_in_library) == set([Path(IGNORE_NAME), Path("FOO.MD")])
-
-
-@pytest.mark.parametrize("library", [TemporaryDirectory()], indirect=True)
-def test_refresh_multi_byte_filenames(library: Library):
-    library_dir = unwrap(library.library_dir)
-    # Given
-    registry = RefreshTracker(library=library)
-    library.included_files.clear()
-    (library_dir / ".TagStudio").mkdir()
-    (library_dir / "こんにちは.txt").touch()
-    (library_dir / "em–dash.txt").touch()
-    (library_dir / "apostrophe’.txt").touch()
-    (library_dir / "umlaute äöü.txt").touch()
-
-    # Test if all files were added with their correct names and without exceptions
-    list(registry.refresh_dir(library_dir))
-    assert Path("こんにちは.txt") in registry.files_not_in_library
-    assert Path("em–dash.txt") in registry.files_not_in_library
-    assert Path("apostrophe’.txt") in registry.files_not_in_library
-    assert Path("umlaute äöü.txt") in registry.files_not_in_library
diff --git a/tests/core/library/test_sync.py b/tests/core/library/test_sync.py
new file mode 100644
index 00000000..b9b071fe
--- /dev/null
+++ b/tests/core/library/test_sync.py
@@ -0,0 +1,406 @@
+# SPDX-FileCopyrightText: (c) TagStudio Contributors
+# SPDX-License-Identifier: GPL-3.0-only
+
+# pyright: reportPrivateUsage=false
+
+import os
+import unicodedata
+from pathlib import Path
+from tempfile import TemporaryDirectory
+
+import pytest
+
+from tagstudio.core.constants import IGNORE_NAME, TS_FOLDER_NAME
+from tagstudio.core.library.alchemy.enums import BrowsingState
+from tagstudio.core.library.alchemy.library import Library
+from tagstudio.core.library.alchemy.models import Entry
+from tagstudio.core.library.sync import LibrarySyncEngine
+from tagstudio.core.utils.types import unwrap
+
+
+@pytest.mark.parametrize("library", [TemporaryDirectory()], indirect=True)
+def test_sync_new_files(library: Library):
+    """New files that aren't excluded by an ignore pattern must be picked up as new."""
+    library_dir = unwrap(library.library_dir)
+    engine = LibrarySyncEngine(library=library)
+    (library_dir / "foo.md").touch()
+    (library_dir / "bar.txt").touch()
+    ts_ignore_path = library_dir / TS_FOLDER_NAME / IGNORE_NAME
+    ts_ignore_path.parent.mkdir(parents=True, exist_ok=True)
+    ts_ignore_path.write_text("*.md")
+
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    assert set(engine.new_paths) == {Path("bar.txt")}
+
+
+@pytest.mark.parametrize("library", [TemporaryDirectory()], indirect=True)
+def test_sync_multi_byte_filenames(library: Library):
+    """Multi-byte and accented Unicode filenames must be scanned and added without errors."""
+    library_dir = unwrap(library.library_dir)
+    engine = LibrarySyncEngine(library=library)
+    (library_dir / ".TagStudio").mkdir()
+    (library_dir / "こんにちは.txt").touch()
+    (library_dir / "em–dash.txt").touch()
+    (library_dir / "apostrophe’.txt").touch()
+    (library_dir / "umlaute äöü.txt").touch()
+
+    list(engine.sync_dir(library_dir))
+    assert Path("こんにちは.txt") in engine.new_paths
+    assert Path("em–dash.txt") in engine.new_paths
+    assert Path("apostrophe’.txt") in engine.new_paths
+    assert Path("umlaute äöü.txt") in engine.new_paths
+
+
+@pytest.mark.parametrize("library", [TemporaryDirectory()], indirect=True)
+def test_sync_unlinked_entries(library: Library):
+    """An unlinked entry with one matching file must be found by `relink_unlinked_entries()`."""
+    library_dir = unwrap(library.library_dir)
+    engine = LibrarySyncEngine(library=library)
+
+    # Touch the file "bar.md" but in the wrong location, to simulate a moved file
+    (library_dir / "bar.md").touch()
+
+    # Neither library entry ("foo.txt", "one/two/bar.md") exists on disk, so both are unlinked
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    assert engine.unlinked_entries_count == 2
+
+    # Relinking bar.md should match and relink to the entry that was at "one/two/bar.md"
+    list(engine.relink_unlinked_entries())
+    assert engine.manual_relink_count == 1
+    assert engine.unlinked_entries_count == 1
+
+    results = library.search_library(BrowsingState.from_path("bar.md"), page_size=500)
+    entries = library.get_entries(results.ids)
+    assert entries[0].path == Path("bar.md")
+
+
+@pytest.mark.parametrize("library", [TemporaryDirectory()], indirect=True)
+def test_sync_nfd_nfc_false_positive(library: Library):
+    """A file reappearing in a different Unicode form must not look like a new/duplicate entry."""
+    library_dir = unwrap(library.library_dir)
+    engine = LibrarySyncEngine(library=library)
+
+    nfc_name = unicodedata.normalize("NFC", "SKÅL.txt")
+    nfd_name = unicodedata.normalize("NFD", "SKÅL.txt")
+    assert nfc_name != nfd_name
+
+    (library_dir / nfc_name).touch()
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    list(engine.save_new_entries())
+
+    # Simulate the file later showing up in NFD form, as if the filesystem was changed
+    (library_dir / nfc_name).unlink()
+    (library_dir / nfd_name).touch()
+
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    assert engine.new_paths == []
+    assert len(engine.paths_to_restat) == 1
+    assert engine.unlinked_entries_count == 2
+
+
+@pytest.mark.parametrize("library", [TemporaryDirectory()], indirect=True)
+def test_sync_case_sensitivity_aware_relink(library: Library):
+    """`find_relink_candidates()` must respect the library's case-sensitivity setting."""
+    library_dir = unwrap(library.library_dir)
+    engine = LibrarySyncEngine(library=library)
+
+    (library_dir / "Other").mkdir()
+    (library_dir / "Other" / "name.txt").touch()
+    library.add_entries([Entry(path=Path("Folder/Name.txt"), fields=[])])
+
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    unlinked_entry = next(e for e in engine.unlinked_entries if e.path == Path("Folder/Name.txt"))
+
+    library.is_case_sensitive_fs = True
+    assert engine.find_relink_candidates(unlinked_entry) == []
+
+    library.is_case_sensitive_fs = False
+    engine._filename_to_path_map = None  # Rebuild the index with the new case sensitivity
+    assert engine.find_relink_candidates(unlinked_entry) == [Path("Other/name.txt")]
+
+
+@pytest.mark.parametrize("library", [TemporaryDirectory()], indirect=True)
+def test_sync_cache_pruned_on_remove(library: Library):
+    """Removing an unlinked entry must prune the path cache."""
+    library_dir = unwrap(library.library_dir)
+    engine = LibrarySyncEngine(library=library)
+
+    tracked_path = Path("tracked.txt")
+    (library_dir / tracked_path).touch()
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    list(engine.save_new_entries())
+
+    (library_dir / tracked_path).unlink()
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    tracked_entry = next(e for e in engine.unlinked_entries if e.path == tracked_path)
+
+    cache = library.get_or_build_path_cache()
+    assert tracked_path in cache
+
+    # Only an explicit removal should prune the cache
+    engine.unlinked_entries = [tracked_entry]
+    engine.remove_unlinked_entries()
+    assert tracked_path not in cache
+
+    # A different file at the same path afterwards should be treated as new
+    (library_dir / tracked_path).touch()
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    assert engine.new_paths == [tracked_path]
+
+
+@pytest.mark.parametrize("library", [TemporaryDirectory()], indirect=True)
+def test_sync_duplicate_case_collision_treated_as_unlinked(library: Library):
+    """A duplicate entry displaced by a case-insensitive collision must be treated as unlinked."""
+    library_dir = unwrap(library.library_dir)
+    engine = LibrarySyncEngine(library=library)
+    library.is_case_sensitive_fs = False  # Force a collision using a case difference
+
+    (library_dir / "Dupe").mkdir()
+    (library_dir / "Dupe" / "photo.jpg").touch()
+    entry_a_id, entry_b_id = library.add_entries(
+        [
+            Entry(path=Path("Dupe/photo.jpg"), fields=[]),
+            Entry(path=Path("Dupe/PHOTO.JPG"), fields=[]),
+        ]
+    )
+
+    cache = library.get_or_build_path_cache()
+    path_key = Path("dupe/photo.jpg")  # Case-insensitive + NFD
+    assert library.duplicate_path_entry_ids is not None
+    assert len(library.duplicate_path_entry_ids) == 1
+    dupe_id = library.duplicate_path_entry_ids[0]
+    original_id = entry_b_id if dupe_id == entry_a_id else entry_a_id
+    assert cache.get(path_key) == original_id
+
+    # The dupe ID should be marked as unlinked, and the original ID should not
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    unlinked_ids = {e.id for e in engine.unlinked_entries}
+    assert dupe_id in unlinked_ids
+    assert original_id not in unlinked_ids
+
+    # Removing the duplicate entry shouldn't remove the original from the cache
+    engine.unlinked_entries = [e for e in engine.unlinked_entries if e.id == dupe_id]
+    engine.remove_unlinked_entries()
+    assert cache.get(path_key) == original_id
+    assert library.duplicate_path_entry_ids == []
+
+
+@pytest.mark.parametrize("library", [TemporaryDirectory()], indirect=True)
+def test_sync_auto_relink_moved_file(library: Library):
+    """A moved file (same filename + stats, different path) must auto-relink to its entry."""
+    library_dir = unwrap(library.library_dir)
+    engine = LibrarySyncEngine(library=library)
+
+    (library_dir / "moveme.txt").touch()
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    list(engine.save_new_entries())
+    original_id = library.get_entry_id_from_path(Path("moveme.txt"))
+    assert original_id >= 0
+
+    (library_dir / "sub").mkdir()
+    (library_dir / "moveme.txt").rename(library_dir / "sub" / "moveme.txt")
+
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    assert engine.new_paths == []
+    assert engine.relinked_entries_count == 1
+    assert engine.relinked_entries[0].id == original_id
+    assert Path("sub/moveme.txt") not in {e.path for e in engine.unlinked_entries}
+    assert library.get_entry_id_from_path(Path("sub/moveme.txt")) == original_id
+    # The original path should no longer be associated with an entry
+    assert library.get_entry_id_from_path(Path("moveme.txt")) == -1
+
+
+@pytest.mark.parametrize("library", [TemporaryDirectory()], indirect=True)
+def test_sync_auto_relink_moved_file_ambiguous(library: Library):
+    """Two equally-matching candidates (same filename + stats) must not auto-relink.
+
+    NOTE: This may change in the future as capability expands.
+    """
+    library_dir = unwrap(library.library_dir)
+    engine = LibrarySyncEngine(library=library)
+
+    (library_dir / "a").mkdir()
+    (library_dir / "b").mkdir()
+    (library_dir / "a" / "dupe.txt").touch()
+    (library_dir / "b" / "dupe.txt").touch()
+    st = (library_dir / "a" / "dupe.txt").stat()
+    os.utime(library_dir / "b" / "dupe.txt", (st.st_atime, st.st_mtime))
+
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    list(engine.save_new_entries())
+
+    (library_dir / "a" / "dupe.txt").unlink()
+    (library_dir / "b" / "dupe.txt").unlink()
+    (library_dir / "c").mkdir()
+    (library_dir / "c" / "dupe.txt").touch()
+    os.utime(library_dir / "c" / "dupe.txt", (st.st_atime, st.st_mtime))
+
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    assert engine.relinked_entries_count == 0
+    assert Path("c/dupe.txt") in engine.new_paths
+    unlinked_paths = {e.path for e in engine.unlinked_entries}
+    assert Path("a/dupe.txt") in unlinked_paths
+    assert Path("b/dupe.txt") in unlinked_paths
+
+
+@pytest.mark.parametrize("library", [TemporaryDirectory()], indirect=True)
+def test_sync_auto_relink_moved_file_stat_mismatch(library: Library):
+    """A file with (same filename, different stats) must not auto-relink.
+
+    NOTE: This is a limitation of the current auto-relinking system, NOT a design principle.
+    """
+    library_dir = unwrap(library.library_dir)
+    engine = LibrarySyncEngine(library=library)
+
+    (library_dir / "notmoved.txt").touch()
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    list(engine.save_new_entries())
+
+    (library_dir / "notmoved.txt").unlink()
+    (library_dir / "sub").mkdir()
+    (library_dir / "sub" / "notmoved.txt").touch()
+
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    assert engine.relinked_entries_count == 0
+    assert Path("sub/notmoved.txt") in engine.new_paths
+    assert Path("notmoved.txt") in {e.path for e in engine.unlinked_entries}
+
+
+@pytest.mark.parametrize("library", [TemporaryDirectory()], indirect=True)
+def test_sync_auto_relink_renamed_file(library: Library):
+    """A renamed file (different filename, same stats) must auto-relink to its entry."""
+    library_dir = unwrap(library.library_dir)
+    engine = LibrarySyncEngine(library=library)
+
+    (library_dir / "original_name.txt").touch()
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    list(engine.save_new_entries())
+    original_id = library.get_entry_id_from_path(Path("original_name.txt"))
+    assert original_id >= 0
+
+    (library_dir / "original_name.txt").rename(library_dir / "renamed.txt")
+
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    assert engine.new_paths == []
+    assert engine.relinked_entries_count == 1
+    assert engine.relinked_entries[0].id == original_id
+    assert Path("renamed.txt") not in {e.path for e in engine.unlinked_entries}
+    assert library.get_entry_id_from_path(Path("renamed.txt")) == original_id
+    # The original path should no longer be associated with an entry
+    assert library.get_entry_id_from_path(Path("original_name.txt")) == -1
+
+
+@pytest.mark.parametrize("library", [TemporaryDirectory()], indirect=True)
+def test_sync_auto_relink_renamed_file_ambiguous(library: Library):
+    """Two equally-matching candidates (different filenames, same stats) must not auto-relink.
+
+    NOTE: This may be automated in the future, but for now differs to the user's judgement.
+    """
+    library_dir = unwrap(library.library_dir)
+    engine = LibrarySyncEngine(library=library)
+
+    (library_dir / "a").mkdir()
+    (library_dir / "b").mkdir()
+    (library_dir / "a" / "one.txt").touch()
+    (library_dir / "b" / "two.txt").touch()
+    st = (library_dir / "a" / "one.txt").stat()
+    os.utime(library_dir / "b" / "two.txt", (st.st_atime, st.st_mtime))
+
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    list(engine.save_new_entries())
+
+    (library_dir / "a" / "one.txt").unlink()
+    (library_dir / "b" / "two.txt").unlink()
+    (library_dir / "c").mkdir()
+    (library_dir / "c" / "renamed.txt").touch()
+    os.utime(library_dir / "c" / "renamed.txt", (st.st_atime, st.st_mtime))
+
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    assert engine.relinked_entries_count == 0
+    assert Path("c/renamed.txt") in engine.new_paths
+    unlinked_paths = {e.path for e in engine.unlinked_entries}
+    assert Path("a/one.txt") in unlinked_paths
+    assert Path("b/two.txt") in unlinked_paths
+
+
+@pytest.mark.parametrize("library", [TemporaryDirectory()], indirect=True)
+def test_sync_auto_relink_moved_and_renamed_together(library: Library):
+    """A moved file and a renamed file in the same sync must each auto-relink via their own pass."""
+    library_dir = unwrap(library.library_dir)
+    engine = LibrarySyncEngine(library=library)
+
+    (library_dir / "moveme.txt").touch()
+    (library_dir / "rename_orig.txt").touch()
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    list(engine.save_new_entries())
+    moved_id = library.get_entry_id_from_path(Path("moveme.txt"))
+    renamed_id = library.get_entry_id_from_path(Path("rename_orig.txt"))
+    assert moved_id >= 0
+    assert renamed_id >= 0
+
+    (library_dir / "sub").mkdir()
+    (library_dir / "moveme.txt").rename(library_dir / "sub" / "moveme.txt")
+    (library_dir / "rename_orig.txt").rename(library_dir / "rename_new.txt")
+
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    assert engine.new_paths == []
+    assert engine.relinked_entries_count == 2
+    assert {e.id for e in engine.relinked_entries} == {moved_id, renamed_id}
+    assert library.get_entry_id_from_path(Path("sub/moveme.txt")) == moved_id
+    assert library.get_entry_id_from_path(Path("rename_new.txt")) == renamed_id
+
+
+@pytest.mark.parametrize("library", [TemporaryDirectory()], indirect=True)
+def test_sync_cancel_skips_unlinked_finalization(library: Library):
+    """A cancelled `sync_dir()` call must not mark any entries as unlinked."""
+    library_dir = unwrap(library.library_dir)
+    engine = LibrarySyncEngine(library=library)
+
+    (library_dir / "a.txt").touch()
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    list(engine.save_new_entries())
+    baseline_unlinked_count = engine.unlinked_entries_count
+
+    # Case where sync is cancelled before this scan even starts
+    engine.cancelled = True
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    assert engine.unlinked_entries_count == baseline_unlinked_count
+    assert engine.new_paths == []
+
+
+@pytest.mark.parametrize("library", [TemporaryDirectory()], indirect=True)
+def test_sync_cancel_skips_save_new_entries(library: Library):
+    """A cancelled `save_new_entries()` call must not save any new entries."""
+    library_dir = unwrap(library.library_dir)
+    engine = LibrarySyncEngine(library=library)
+
+    baseline_count = library.entries_count
+
+    (library_dir / "f0.txt").touch()
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    assert engine.new_paths == [Path("f0.txt")]
+
+    engine.cancelled = True
+    list(engine.save_new_entries())
+    assert library.entries_count == baseline_count
+    assert engine.new_paths == [Path("f0.txt")]
+
+
+@pytest.mark.parametrize("library", [TemporaryDirectory()], indirect=True)
+def test_sync_cancel_skips_sync_entry_stats(library: Library):
+    """A cancelled `sync_entry_stats()` call must not touch `paths_to_restat`."""
+    library_dir = unwrap(library.library_dir)
+    engine = LibrarySyncEngine(library=library)
+
+    (library_dir / "f0.txt").touch()
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    list(engine.save_new_entries())
+
+    # A second scan finds the same file again, marking it for a restat
+    list(engine.sync_dir(library_dir, force_internal_scanner=True))
+    assert len(engine.paths_to_restat) == 1
+    expected = list(engine.paths_to_restat)
+
+    engine.cancelled = True
+    list(engine.sync_entry_stats())
+    assert engine.paths_to_restat == expected
diff --git a/tests/core/library/test_unlinked_entries.py b/tests/core/library/test_unlinked_entries.py
deleted file mode 100644
index 4d20590c..00000000
--- a/tests/core/library/test_unlinked_entries.py
+++ /dev/null
@@ -1,38 +0,0 @@
-# SPDX-FileCopyrightText: (c) TagStudio Contributors
-# SPDX-License-Identifier: GPL-3.0-only
-
-
-from pathlib import Path
-from tempfile import TemporaryDirectory
-
-import pytest
-
-from tagstudio.core.library.alchemy.enums import BrowsingState
-from tagstudio.core.library.alchemy.library import Library
-from tagstudio.core.library.alchemy.registries.unlinked_registry import UnlinkedRegistry
-from tagstudio.core.utils.types import unwrap
-
-CWD = Path(__file__).parent
-
-
-# NOTE: Does this test actually work?
-@pytest.mark.parametrize("library", [TemporaryDirectory()], indirect=True)
-def test_refresh_unlinked_entries(library: Library):
-    registry = UnlinkedRegistry(lib=library)
-
-    # touch the file `one/two/bar.md` but in wrong location to simulate a moved file
-    (unwrap(library.library_dir) / "bar.md").touch()
-
-    # no files actually exist, so it should return all entries
-    assert list(registry.refresh_unlinked_files()) == [0, 1]
-
-    # neither of the library entries exist
-    assert len(registry.unlinked_entries) == 2
-
-    # iterate through two files
-    assert list(registry.fix_unlinked_entries()) == [0, 1]
-
-    # `bar.md` should be relinked to new correct path
-    results = library.search_library(BrowsingState.from_path("bar.md"), page_size=500)
-    entries = library.get_entries(results.ids)
-    assert entries[0].path == Path("bar.md")
diff --git a/tests/fixtures/search_library/.TagStudio/ts_library.sqlite b/tests/fixtures/search_library/.TagStudio/ts_library.sqlite
index 485e54a8..33d95a4e 100644
Binary files a/tests/fixtures/search_library/.TagStudio/ts_library.sqlite and b/tests/fixtures/search_library/.TagStudio/ts_library.sqlite differ
diff --git a/tests/qt/test_file_path_options.py b/tests/qt/test_file_path_options.py
index a5ab0edb..000b17c8 100644
--- a/tests/qt/test_file_path_options.py
+++ b/tests/qt/test_file_path_options.py
@@ -134,7 +134,7 @@ def test_title_update(
     qt_driver.main_window.menu_bar.ignore_modal_action = QAction(menu_bar)
     qt_driver.main_window.menu_bar.save_library_backup_action = QAction(menu_bar)
     qt_driver.main_window.menu_bar.close_library_action = QAction(menu_bar)
-    qt_driver.main_window.menu_bar.refresh_dir_action = QAction(menu_bar)
+    qt_driver.main_window.menu_bar.sync_library_action = QAction(menu_bar)
     qt_driver.main_window.menu_bar.tag_manager_action = QAction(menu_bar)
     qt_driver.main_window.menu_bar.color_manager_action = QAction(menu_bar)
     qt_driver.main_window.menu_bar.new_tag_action = QAction(menu_bar)