How to Verify a FreeFileSync Sync Completed Correctly
Verify FreeFileSync results with logs, a second comparison, and representative file checks.
Quick answer
Review the completion log for failed, skipped, retried, or ignored items and confirm the expected destination.
What to check first
Run a second comparison to identify remaining differences, while accounting for filters and exclusions.
Windows-specific factors
Open a recent document, a large file, a deeply nested item, and a file from a special folder on the destination.
Safer troubleshooting workflow
If Mirror or versioning was used, confirm that deletions and retained versions went to the intended locations.
How to verify the result
For important backups, restore samples to a separate folder and record when the last recovery test succeeded.
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