How to compare and sync folders on Windows
Comparing folders answers a different question from copying them. A copy command asks where data should go; a comparison first shows how the source and target differ. That review is essential when a network library or server folder already contains files.
Reviewed:
A useful comparison separates change types
- New: present in the source but not at the target.
- Modified: the same relative path exists but the file content or attributes differ.
- Renamed: equivalent content is detected under a different relative path where possible.
- Target-only or deleted: present at the target but absent from the source.
LibSync shows the one-way folder diff, asks for confirmation and protects existing files before destructive changes. Review LibSync features
Why timestamps alone are not enough
File timestamps can change during extraction, migration or server processing. Size helps, but two same-sized files can still contain different data. LibSync's comparison uses file information and content hashing where needed to determine a practical diff.
Comparison cannot tell you which human decision is correct. If both sides were edited independently, choose the authoritative version outside the tool before running a one-way sync.
Preview is a decision point, not decoration
A useful preview lists relative paths and statuses and summarises the file count and volume. Large unexpected totals, an apparently empty source or many target-only files are reasons to stop and check connectivity, profile selection and ownership.
LibSync creates one plan for the review and run so the accepted operation set stays consistent. If the file system changes or becomes unreachable, treat that as a failed maintenance window and build a fresh plan.
Filters, backups and deletions
Profiles can exclude selected file extensions. Use that for predictable temporary or generated formats, but do not turn a long exclusion list into a substitute for a clean source folder.
Existing files are backed up before overwrite, rename-related replacement or deletion. With deletion sync off, target-only files can be reviewed as orphans. There is no automatic conflict resolution or continuous background watcher.
Read a folder comparison
Review high-impact states first, then confirm the ordinary additions.
- 1
Confirm source and target labels
A reversed profile can apply the right comparison in the wrong direction.
- 2
Check reachability warnings
An unavailable source or skipped reparse point must be investigated before deletions.
- 3
Review target-only files
Decide whether they are obsolete, evidence of another publisher or material that must be copied back explicitly.
- 4
Inspect modified and renamed paths
Check important files and unexpected folder moves before accepting them.
- 5
Scan additions and exclusions
Confirm that new files belong in the destination and excluded extensions are intentional.
- 6
Run and read the failure count
A summary with failures needs follow-up and a new preview after the cause is fixed.
Stop the sync when
- The source is empty or unexpectedly small.
- The selected profile points in the wrong direction.
- A network path is intermittent or access rights changed.
- Target-only files suggest somebody edited the destination.
- The change volume cannot be explained by the planned release.
Windows folder comparison FAQ
Does preview modify any files?
No. Preview scans and reports the planned operations. Writes occur only after the user confirms and runs the synchronization.
Can I exclude folders?
The confirmed profile option is an excluded-extension list. Use folder structure and a clean source to keep unwanted directories out of the sync set.
Does LibSync detect conflicts?
It detects differences, but it does not provide two-way conflict resolution. The operator must decide which source version is authoritative.
Related guides
Continue with the next practical question in this workflow.