Help & Technical Support

How to install DirMerge on macOS

1. Download the DirMerge.dmg installer.

2. Double-click the downloaded .dmg file to mount the disk image.

3. Drag the DirMerge icon into your Applications folder.

4. Launch DirMerge from Launchpad or Spotlight (⌘Space).

How to open if macOS shows an unidentified developer warning

If your Mac displays a security notification upon first launch, simply right-click (or Control-click) the DirMerge.app icon in your Applications folder and select Open, then click Open in the confirmation dialog. Alternatively, navigate to System Settings > Privacy & Security and click Open Anyway.

Does DirMerge overwrite my source folder?

Never. The Source directory is strictly treated as read-only. DirMerge will never delete, move, or modify any file within your Source directory under any circumstances.

What is APFS Zero-Space Cloning?

When both your Source and Target directories reside on the same APFS formatted volume (such as your internal Mac SSD or an APFS external drive), macOS supports Copy-on-Write cloning. DirMerge clones files in milliseconds without duplicating physical disk blocks until one of the copies is modified.

What happens if a file with the same name already exists in Target?

Before replacing any existing file in the Target directory, DirMerge creates a safe rollback snapshot in a hidden .dirmerge/backups folder inside your target directory. If you make a mistake, simply press ⌘Z to restore all overwritten files.

Does DirMerge work with external USB drives, SD cards, and ExFAT?

Yes. DirMerge detects whether a folder is located on an internal disk or external USB drive. If the drive does not support APFS cloning (e.g. ExFAT, FAT32, or HFS+), DirMerge automatically falls back to standard high-speed file transfer with safety pre-backups.

How do I restore my Pro purchase on a new Mac?

Open DirMerge, click the Unlock Pro button, and click Restore Purchase at the bottom of the paywall window. Since purchases are tied to your Apple ID via StoreKit, it will unlock instantly without charging you again.