FreeFileSync Long File Path Problems on Windows
Troubleshoot long paths, deep folders, and filename problems when FreeFileSync cannot process Windows files.
Quick answer
Capture the exact failing path and error from the log before changing Windows or renaming production data.
What to check first
Test the same item in a shallow temporary folder to separate path-depth problems from permissions or file corruption.
Windows-specific factors
NAS devices, older applications, archives, and cross-platform filesystems can impose different filename and path limits.
Safer troubleshooting workflow
Avoid bulk renaming until the cause is proven on a copy; preserve a mapping if names must change.
How to verify the result
After correcting the issue, run a fresh comparison and verify planned actions before synchronization.
Frequently asked questions
Should I change sync mode to fix this?
Not until the underlying cause is identified. First verify paths, permissions, comparison results, and logs.
Is a successful sync the same as a verified backup?
No. Important data should be checked at the destination and periodically restored to a separate location.
Related: all FreeFileSync Windows guides