How to Sync Two Folders on a Mac Safely

To sync two folders on a Mac, compare them in a folder-sync utility, choose which direction changes should flow, preview the proposed operations, and then run the sync. SyncTwoFolders includes a simulation step, but its developer warns that a sync can replace older files and remove some files. Treat it as a file-transfer tool, not a versioned backup. The current developer page lists a three-day trial and a suggested €9 retail price, with separate builds for Apple silicon and Intel Macs.

Before you begin: protect the right copy

Decide which folder is the starting point. Use one-way sync when one folder is the master; use two-way only when edits may come from either location. Keep an independent copy of important files, and confirm the folders are different and contain no unresolved same-name conflicts.

How to sync two folders with SyncTwoFolders

1. Identify and prepare both folders

   In Finder, open both folders and check their paths and contents. Connect an external drive before opening the app. Avoid selecting the same folder twice or a folder and its own parent, which can make results unpredictable. For the first run, remove temporary files you do not want copied.

2. Download the build for your Mac

   Download from the developer’s SyncTwoFolders page. It lists a Mac ARM build for macOS 11 or later and an Intel build for macOS 10.14 or later, both marked notarized. Choose the matching build and follow its installation instructions. The app is shareware with a three-day trial and suggested €9 price; check the current license terms.

3. Choose the source, target, and direction

   Set the source to the folder whose contents should drive a one-way update and the target to the destination. Recheck both paths before choosing a mode. Use one-way sync when changes should flow only from source to target; choose reciprocal sync only if both folders can change. A replace-style mode can remove target-only items. Check the in-app help tags; options and labels may vary by version.

4. Run a simulation and inspect the proposed changes

   Choose Simulation before applying changes. The developer says the preview shows planned work without replacing or removing files. Check for unexpected deletions, overwrites, duplicate names, or wrong paths. If the app lists individual operations with checkboxes, deselect unwanted items. If anything is unclear, stop and recheck the paths and mode.

5. Apply the sync and verify the destination

   Proceed only when the preview matches your intent. Keep both locations available until the run ends, then review the log. In Finder, confirm several destination files, including a changed file and one in a subfolder. For a new setup, test with disposable folders to see how the mode handles additions, edits, and removals.

Choose a mode that matches your goal

These descriptions explain the intent, not a promise about the exact wording in every release. Follow the in-app help for the selected option. The official page warns that older files may be replaced and, in some cases, files may be removed; a simulation is the safest way to catch an unexpected result.

When iCloud Drive or Time Machine is a better fit

If you want files across Apple devices, store them in iCloud Drive and turn on Sync this Mac; Desktop & Documents can be added too. Changes and deletions can propagate to your other devices, so cloud sync is not an independent backup. See Apple’s iCloud Drive setup instructions and its guide to syncing Desktop and Documents.

For recovery or a full Mac backup, set up Time Machine with a separate disk. Apple says it keeps hourly, daily, and weekly backups. Read Apple’s Time Machine setup guide.

Frequently asked questions

Is SyncTwoFolders still free?

No. The developer lists shareware, a three-day trial, and a suggested €9 price. Check the official page for current terms.

Can Finder continuously sync any two folders?

Finder can merge some same-name folders once, but it does not provide recurring comparisons for arbitrary folder pairs. Use iCloud Drive for cloud access, Time Machine for backups, or a sync utility for a deliberate folder-to-folder run.