FreeFileSync stopped updating
- Posts: 5
- Joined: 31 May 2026
I've been using FreeFileSync for several years and am currently using ver. 14.9. I use two-way updating between my laptop and desktop, using file time and size. I use one-way mirroring between my laptop and detachable USB drive. I've never had problems until this past week. My PCs are Win 11 with the latest updates. Several days ago, the program stopped updating files, both two-way, computer to computer, and one-way mirroring between computer and removable USB. I update files and then run the program. The program indicates success. But the files that were modified were not actually updated. The files in question were both word documents and spreadsheets. Any thoughts on why...and what the solution might be? Thnaks.
- Posts: 8
- Joined: 5 Apr 2026
Test using a small test file (.txt), not Word (due to locks)
Check FFS-Config (if available): Are any filter rules active?
Check FFS-Config (if available): Are any filter rules active?
- Posts: 5
- Joined: 31 May 2026
To clarify,
(1) I use libreoffice (current version) and save files in docx and xlsx format.
(2) When syncing to my second PC, I use the 'two way' sync protocol.
(3) When syncing to the removable USB drive, I use the 'mirror' protocol.
(4) The only filter I use is *\$Recycle.Bin\.
(5) Both computers are running on Win11, fully updated.
I created two new documents in libreoffice. One document was saved as test.txt and the second was saved as test.docx. I ran the FreeFileSync mirror protocol to my removable USB drive. The test.docx file transferred to the USB, although, it did not show as being transferred during the operation, as it always used to do. The test.txt file did not transfer to the USB drive.
I then ran the 'Two way' protocol to my second PC. Neither file transferred to the second PC. The program did not show any errors. The last time I successfully ran the FreeFileSync program to the second PC was on May 26, 2026.
Should I uninstall FreeFileSync and then reinstall it? Or is the root cause of this problem related to the latest Windows update? Any thoughts you have would be appreciated.
(1) I use libreoffice (current version) and save files in docx and xlsx format.
(2) When syncing to my second PC, I use the 'two way' sync protocol.
(3) When syncing to the removable USB drive, I use the 'mirror' protocol.
(4) The only filter I use is *\$Recycle.Bin\.
(5) Both computers are running on Win11, fully updated.
I created two new documents in libreoffice. One document was saved as test.txt and the second was saved as test.docx. I ran the FreeFileSync mirror protocol to my removable USB drive. The test.docx file transferred to the USB, although, it did not show as being transferred during the operation, as it always used to do. The test.txt file did not transfer to the USB drive.
I then ran the 'Two way' protocol to my second PC. Neither file transferred to the second PC. The program did not show any errors. The last time I successfully ran the FreeFileSync program to the second PC was on May 26, 2026.
Should I uninstall FreeFileSync and then reinstall it? Or is the root cause of this problem related to the latest Windows update? Any thoughts you have would be appreciated.
- Posts: 8
- Joined: 5 Apr 2026
maybe, FFS cache is corrupted
The bidirectional protocol uses an .ffs_db cache file for tracking. If this file is corrupted:
FFS forgets what has already been synced
Does not display any errors
Stops transferring data
1. Close all FFS windows
2. Go to:
C:\Users\[your_username]\AppData\Local\FreeFileSync
3. DELETE (or rename) the ".ffs_db" file
4. Restart FFS → The cache will be rebuilt
5. Run a test synchronization
The bidirectional protocol uses an .ffs_db cache file for tracking. If this file is corrupted:
FFS forgets what has already been synced
Does not display any errors
Stops transferring data
1. Close all FFS windows
2. Go to:
C:\Users\[your_username]\AppData\Local\FreeFileSync
3. DELETE (or rename) the ".ffs_db" file
4. Restart FFS → The cache will be rebuilt
5. Run a test synchronization
- Posts: 5
- Joined: 31 May 2026
First, thank you for your suggestions. I deleted the .ffs_db files and tried again. I had the same issues with not getting a log and finding no changes, even though changes were made.
Next, I uninstalled FFS and then reinstalled it, after deleting the .ffs_db files.
I made changes to several files and ran FFS in two-way mode to a second computer. It worked as expected.
Next, I ran FFS in mirror mode to a backup USB drive. It did not find any changes, even though changes were made.
Now I am thinking that I can not use FFS between more than two devices. If I sync between PC1 and PC2, I cannot sync between PC1 and ExtDrv1 because there is only one database produced. Is that the root of the problem, or is there something else going on?
Thanks again.
Next, I uninstalled FFS and then reinstalled it, after deleting the .ffs_db files.
I made changes to several files and ran FFS in two-way mode to a second computer. It worked as expected.
Next, I ran FFS in mirror mode to a backup USB drive. It did not find any changes, even though changes were made.
Now I am thinking that I can not use FFS between more than two devices. If I sync between PC1 and PC2, I cannot sync between PC1 and ExtDrv1 because there is only one database produced. Is that the root of the problem, or is there something else going on?
Thanks again.
- Posts: 8
- Joined: 5 Apr 2026
FreeFileSync does support multiple sync pairs, but there is a timing issue with USB flash drives:
PC1 ↔ PC2 (bidirectional) → .ffs_db remains on BOTH systems
→ works
PC1 → USB (mirroring) → .ffs_db is saved to USB
→ But USB is "external" & portable
→ Next time it's plugged in:
Use OLD DB → no changes detected
Mirroring WITHOUT database (safest method)
1. FFS configuration: Bottom right
2. → Turn "Use database" OFF
3. → FFS uses only timestamps/size
4. Works reliably with USB
PC1 ↔ PC2 (bidirectional) → .ffs_db remains on BOTH systems
→ works
PC1 → USB (mirroring) → .ffs_db is saved to USB
→ But USB is "external" & portable
→ Next time it's plugged in:
Use OLD DB → no changes detected
Mirroring WITHOUT database (safest method)
1. FFS configuration: Bottom right
2. → Turn "Use database" OFF
3. → FFS uses only timestamps/size
4. Works reliably with USB
- Posts: 5
- Joined: 31 May 2026
This issue has been resolved. Thank you, HeinzB!
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- Site Admin
- Posts: 7506
- Joined: 9 Dec 2007
No, that's not how it works. Sorry I don't have much time currently, just wanted to clarify that it doesn't make a difference for "mirroring" if DB is used or not. DB is generally superior because it detects file renames/moves.PC1 → USB (mirroring) → .ffs_db is saved to USB
→ But USB is "external" & portable
→ Next time it's plugged in:
Use OLD DB → no changes detected HeinzB, 01 Jun 2026, 17:27
- Posts: 5
- Joined: 31 May 2026
As a follow up, none of the fixes I tried worked. I finally uninstalled freefilesync from the PCs on my 4-PC home network. Then I deleted all the backup files and databases that weren't deleted during the uninstall process. I reinstalled freefilesync on the four PCs. It worked great for several days, synchronizing files using the two-way synchronization, based on date, time, and file size. Then, it suddenly stopped synchronizing again. I update files on one PC and then run freefilesync. The program indicates that the process was successful. But, It didn't actually update anything on the second computer. The files on the second PC are still date-stamped 06/10/2026, while the file on the initiating PC are date-stamped 16/13/2026. What am I missing? Help.
