How do you mirror a folder on a Mac without deleting files?

By Kayabyte · Last updated 13 November 2026

Short answer: A true mirror deletes from the copy whatever you deleted from the original, so “mirror without deleting” means moving those files somewhere instead. With rsync you can do that with --backup and --backup-dir, which put replaced and deleted files in a folder you name. Or skip --delete and accept that the copy only grows. Pairfold does the archive version by default: in Mirror mode, anything it would replace or remove goes to a dated archive folder, and the preview lists those files before the run.

Why it matters

Mirror mode copies in one direction and makes the destination identical. If you delete a folder by accident and run the mirror again, the copy loses it as well. The cure is either not to delete (the copy grows without limit) or to keep what would have been deleted.

Method 1: rsync without `--delete`

rsync -av ~/Documents/ /Volumes/Backup/Documents/ copies new and changed files and never removes anything from the destination. Files you deleted at the source stay in the copy forever, and a file you changed is overwritten, so the old version is gone.

Method 2: rsync with a backup folder

rsync -av --delete --backup --backup-dir=/Volumes/Backup/Archive/2026-11-13 ~/Documents/ /Volumes/Backup/Documents/

Replaced and deleted files go to the backup directory instead of vanishing. The macOS man page says to use an absolute path outside the copied tree: a relative one sits inside it and can be affected by --delete. You choose a new folder name for every run yourself, for example with the date, or each run mixes into the last.

Method 3: Time Machine

It keeps versions and deleted files for you, for the whole Mac. See Time Machine vs folder sync.

With Pairfold

In Mirror mode the first folder is never changed. Files that are new or changed are copied; files that are replaced or no longer exist at the source are moved to an archive folder, one dated folder per run, by default a hidden folder named .pairfold-archive on the same disk. You can choose another archive folder, and you can set the archive to be emptied after 30 days, 90 days or a year, or never. Nothing is pruned on its own unless you set it.

If a run would replace or archive a large share of your files, Pairfold asks you to confirm in the preview, and a scheduled run does not go ahead in that case: you get a notification. A missing source disk is never read as “everything deleted”.

Limits: the archive is a plain folder opened in Finder, not a version browser. It uses disk space until you set it to be emptied.

Steps with Pairfold

Click New Pair, choose the source folder first and the copy second.
Choose Mirror.
Click Check and Preview. Items under To archive are what will be moved, not deleted.
Click Sync. Use History, then show the archive in Finder, to find a moved file.

Get Pairfold: see the app page for where to get it

Questions

Can rsync archive deleted files? Yes, with --backup and --backup-dir, as above. You manage the folder names.

Is the archive the same as Time Machine? No. It holds files Pairfold replaced or removed in its own runs. Time Machine backs up the whole Mac on a schedule.

Will the archive fill my drive? It can, if you choose never to empty it. Choose 30 days, 90 days or a year in the pair’s settings.

Apple, Mac, macOS, Finder, Time Machine, and iCloud are trademarks of Apple Inc. Pairfold is made by Kayabyte and is not affiliated with or endorsed by Apple.