I have a Time Machine backup drive (also used for other archival purposes) which has a damaged file-system. I am able to mount it "Read Only," but fsck_hfs will not repair it. *(Apparently it's just a problem with "extended attributes," but this is enough.)

I've ordered a replacement drive, and now I need to know what is the best way to reliably copy all of the information from the old drive to the new, properly preserving permissions and everything else that Time Machine (in particular) requires. Is there, for instance, a Time Machine function to "move backup to a new drive?"

(OS/X Catalina 10.15.3, current.)


The best method to copy (if possible) a Time Machine disk hfs+ to a new one is given by Apple here : https://support.apple.com/guide/mac-help/if-the-time-machine-backup-disk-is-full-mh15137/10.15/mac/10.15

You copy the directory Backups.backupdb from the old disk to the new one by the Finder. It's very long but effective.


I've done bunch of Time Machine transfers, and you don't want to do it the way Apple suggests.

Finder will likely spend days on preparing to transfer, and then it will fail.

Apple doesn't provide a tool to transfer Time Machine data between drives, and more importantly, they don't provide a GUI tool to reconnect that copied drive to your current files, so the next backup acts as if nothing had changed.

The only reliable way to duplicate a Time Machine drive, is with SuperDuper!. It's a looong process, but it works.

See my answer to a similar question, it should give you the info you need:

Why did this dd copy of an encrypted Time Machine drive to another drive seem to have no effect?


"Transfer Time Machine backups from one backup disk to another."


  • 1
    When answering your own quesition please take the time to enter the steps you followed as sometimes these diviate from the cited source and also the original website could change or disappear. Feb 10 '20 at 22:12

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