diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3b099b5..2487868 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -33,6 +33,12 @@ point is tag `upstream-baseline`.
   problems print a message instead of a traceback. With `--json-log`, a run that fails with an unhandled error
   still appends a `run` record carrying `exit_code` and `error`.
 
+### Fixed
+- `Config/dedupe_roots`: a multi-file release whose discs are already hardlinked under *different* library
+  folders (a prior `multibook` run, or a file moved in the library) is no longer reported as already filed.
+  The first folder used to win, `hardlinkUnlessFiled` skipped, and the processed marker then hid the rest of
+  the files on later runs. The `Title/cd1`, `Title/cd2` disc subfolders booktree creates still count as one book.
+
 ### Changed
 - The cookie store is `<log_path>/cookies.json` (owner-readable, written atomically) instead of `cookies.pkl`.
   A pickle from a shared directory was loaded on every run, which executes whatever the file contains; an existing
diff --git a/CONFIG.md b/CONFIG.md
index c040699..d4c27c8 100644
--- a/CONFIG.md
+++ b/CONFIG.md
@@ -262,8 +262,9 @@ when their media files are the same inodes. Before hardlinking a matched release
 in an index of the media files under the listed directories (built once per run); if one is found, the release
 is reported (`Already in the library at ...; not hardlinking ...`, `already_filed` in the JSON log) and left
 alone, but still logged as matched (with its target path) and marked processed. A release counts as filed only
-when every one of its files is, so an interrupted filing is completed on the next run; symlinks in a library do
-not count. Nothing is ever deleted. Typical values are your
+when every one of its files is in the same library book folder (`Title/cd1`, `Title/cd2` disc subfolders count
+as `Title`), so an interrupted or split filing (discs left under two different matches) is completed on the next
+run; symlinks in a library do not count. Nothing is ever deleted. Typical values are your
 `media_path` (stops a second config from filing a clone of a book the first one already filed) or the libraries
 of other users on the same server. A root that contains, or lies inside, a `source_path` is refused, because the
 downloads themselves would then count as already filed.
diff --git a/myx_library.py b/myx_library.py
index 03858f8..8c23d91 100644
--- a/myx_library.py
+++ b/myx_library.py
@@ -14,8 +14,10 @@
 Dedupe: two folders hold the same book when their media files are the same inodes (hardlinks), which is
 exactly how booktree files a download. Before hardlinking a matched book its source files are looked up in an
 index of (device, inode) built once per run from the dedupe roots; a book already present is reported and left
-alone, nothing is ever deleted. A book counts as filed only when every one of its files is (a filing that was
-interrupted half-way is completed, as hardlinkFile skips files that already exist). A root that contains, or lies
+alone, nothing is ever deleted. A book counts as filed only when every one of its files is in the same library
+book folder, where the disc subfolders booktree creates (Title/cd1, Title/cd2) belong to their parent (a filing
+that was interrupted half-way, or split across two folders after a multibook run or a manual move, is completed;
+hardlinkFile skips files that already exist at the new target). A root that contains, or lies
 inside, a source path is refused: the downloads themselves would then count as "already filed" and nothing under
 it would ever be hardlinked.
 """
@@ -25,6 +27,8 @@
 
 import requests
 
+import myx_utilities
+
 TIMEOUT = 30
 LIBRARY_ID = re.compile(r"[A-Za-z0-9_-]{1,64}")      # ABS ids are `lib_...` or UUIDs; anything else would change the URL path
 MEDIA_EXTS = (".m4b", ".mp3", ".m4a", ".flac", ".ogg", ".opus", ".aac", ".wma")
@@ -91,7 +95,13 @@ def _buildIndex(roots):
 
 
 def alreadyFiled(cfg, files):
-    """The library folder that already holds every one of `files` (paths of a book's media files), or None."""
+    """The library folder that already holds every one of `files` (paths of a book's media files), or None.
+
+    Every file must be present *and* they must all belong to the same book folder (disc subfolders such as
+    Title/cd1, Title/cd2 count as their parent): discs filed under two different matches (multibook-on, then off;
+    or a later move in the library) are not "already filed" — hardlinkUnlessFiled should complete the release,
+    where the processed marker would otherwise hide the rest of the files forever.
+    """
     global _index, _indexRoots
     roots = dedupeRoots(cfg)
     if not roots:
@@ -110,7 +120,21 @@ def alreadyFiled(cfg, files):
         if not folder:
             return None
         folders.append(folder)
-    return folders[0] if folders else None
+    if not folders:
+        return None
+    # booktree files a multi-disc book as Title/cd1, Title/cd2 (Config/target_path/disc_folder): those are one
+    # book folder. "Title" next to "Title Disc 2" (a split filing) are not: their parents differ.
+    homes = [_bookFolder(folder) for folder in folders]
+    if any(home != homes[0] for home in homes[1:]):
+        return None
+    return homes[0]
+
+
+def _bookFolder(folder):
+    """The book folder a filed media file belongs to: its directory, or the parent when that is a disc subfolder."""
+    if myx_utilities.isMultiCD(os.path.basename(folder)):
+        return os.path.dirname(folder)
+    return folder
 
 
 # ---------------------------------------------------------------- Audiobookshelf
diff --git a/tests/test_operator_tools.py b/tests/test_operator_tools.py
index 1b8d918..466b62d 100644
--- a/tests/test_operator_tools.py
+++ b/tests/test_operator_tools.py
@@ -357,6 +357,57 @@ def test_every_file_must_be_filed_and_symlinks_do_not_count(self):
         with contextlib.redirect_stdout(io.StringIO()):
             self.assertEqual(myx_library.alreadyFiled(cfg, [self.source_file, second]), target)
 
+    def test_files_in_different_library_folders_are_not_already_filed(self):
+        # multibook-on filed each disc as its own book; or the operator moved one disc in ABS. The inodes are
+        # all in the library, but no single folder holds the release — do not skip, or cacheMe would hide it.
+        cfg = self.cfg(**{"Config/dedupe_roots": [self.lib]})
+        second = os.path.join(self.src, "Some Book", "cd2.m4b")
+        with open(second, "wb") as fh:
+            fh.write(b"\x00" * 16)
+        first_dir = os.path.join(self.lib, "Author", "Some Book")
+        other_dir = os.path.join(self.lib, "Author", "Some Book Disc 2")
+        os.makedirs(other_dir)
+        os.link(self.source_file, os.path.join(first_dir, "cd1.m4b"))
+        os.link(second, os.path.join(other_dir, "cd2.m4b"))
+        with contextlib.redirect_stdout(io.StringIO()):
+            self.assertIsNone(myx_library.alreadyFiled(cfg, [self.source_file, second]))
+        import booktree
+        import myx_classes
+        mb = myx_classes.MAMBook("Some Book")
+        match = myx_classes.Book(asin=ASIN, title="Some Book")
+        match.authors = [myx_classes.Contributor("Author")]
+        for name, path in (("Some Book/book.m4b", self.source_file), ("Some Book/cd2.m4b", second)):
+            bf = myx_classes.BookFile(name, path, self.src, self.lib)
+            bf.ffprobeBook = match
+            mb.files.append(bf)
+        mb.ffprobeBook = mb.bestAudibleMatch = match
+        mb.metadata = "audible"
+        mb.isMatched = True
+        with contextlib.redirect_stdout(io.StringIO()) as out:
+            self.assertTrue(booktree.hardlinkUnlessFiled(mb, cfg))
+        unified = os.path.join(self.lib, "Author", "Some Book")
+        self.assertTrue(os.path.exists(os.path.join(unified, "book.m4b")), out.getvalue())
+        self.assertTrue(os.path.exists(os.path.join(unified, "cd2.m4b")), out.getvalue())
+        self.assertNotIn("Already in the library", out.getvalue())
+
+    def test_disc_subfolders_of_one_book_count_as_already_filed(self):
+        # booktree itself files a multi-disc book as Title/cd1, Title/cd2 (disc_folder): that is one filed book
+        cfg = self.cfg(**{"Config/dedupe_roots": [self.lib]})
+        second = os.path.join(self.src, "Some Book", "cd2.m4b")
+        with open(second, "wb") as fh:
+            fh.write(b"\x00" * 16)
+        title = os.path.join(self.lib, "Author", "Some Book")
+        for disc, source in (("cd1", self.source_file), ("Disc 02", second)):
+            os.makedirs(os.path.join(title, disc))
+            os.link(source, os.path.join(title, disc, os.path.basename(source)))
+        with contextlib.redirect_stdout(io.StringIO()):
+            self.assertEqual(myx_library.alreadyFiled(cfg, [self.source_file, second]), title)
+        # the same discs under two different titles are still a split filing
+        os.rename(os.path.join(title, "Disc 02"), os.path.join(self.lib, "Author", "Other Title"))
+        myx_library.reset()
+        with contextlib.redirect_stdout(io.StringIO()):
+            self.assertIsNone(myx_library.alreadyFiled(cfg, [self.source_file, second]))
+
     def test_pinned_or_refreshed_book_is_filed_even_when_a_copy_exists(self):
         # the copy in the library is the wrong match being corrected: dedupe must not block the pin
         import booktree