MacOS – Continue managing external drive backups on a different computer

backupmacostime-machine

I have an external drive with data on it that is shared on the local network. There's another external drive that's daisy chained where backups are stored.

The computer that was originally managing the backups with Time Machine has been replaced and the drives have been moved to another computer.


The Problem

When I select the backup drive for time machine, it attempts to duplicate all the files again since it doesn't recognize the previous backups since they were made on a different computer.

I have tried using tmutil inheritbackup and tmutil associatedisk but have been hit with a couple errors.

$ sudo tmutil inheritbackup /Volumes/BACKUP_HD/OLD_CPU
Unexpectedly found no machine directories for "/Volumes/BACKUP_HD/OLD_CPU" during collision check.
$ sudo tmutil associatedisk -a /Volumes/DATA_HD /Volumes/BACKUP_HD/OLD_CPU/Latest/DATA_HD
Not a snapshot volume.

Attempting to manage the backups on the new computer ends up trying to duplicate the data again, which is less than ideal.

Best Answer

A simple solution I found is to switch the new computer's name to the old one through System Preferences > Sharing .

Not quite the solution I'm looking for, but it works.