After a clean install of Ventura, I have manually transferred data from when the same Mac had Monterey. I then used tmutil inheritbackup to reconnect to the same external backup disk that I had been using. That command was successful. However, it turns out that my account on Ventura has a different UID than it did under Monterey (despite having the same name). From the resulting mismatch, I not only can't continue from the previous backup, but I have lost access to all the backed up data on the external disk. Is there a way to repair the UID mismatch?

Clarification: Just to add to the challenge, the Mac is bound in a domain, making low level changes to the new install dicey-to-impossible. So a full solution would have to adjust the TM backup instead.

(Preemptive comment: No need to preach the Migration Assistant gospel. It might well have been a better choice, but that is water under the bridge.)

  • What happens when you try to do a backup?
    – Ezekiel
    Jan 12 at 17:18
  • I would bet that trying to "solve" this is much more hassle than simply starting a new TM backup.
    – mhopeng
    Jan 12 at 18:08
  • @Ezekiel I'm afraid that trying that will permanently destroy the TM structure. I've let it go as far as "found XXX changes", but then aborted. Even that has left me with an ".inProgress" directory.
    – James6M
    Jan 13 at 15:29
  • @mhopeng I need to "solve" this at least enough to access the backed up files. Not theoretical; I currently need some of them.
    – James6M
    Jan 13 at 15:32
  • Use finder not Time Machine to access the files, you can force the permissions
    – Ezekiel
    Jan 14 at 18:40

2 Answers 2


You can change the UID from the System Preferences "Users & Groups" panel. Unlock the panel and then right-click on your username and choose "Advanced Preferences". As long as there is no other user with the same UID, this should not be a problem. Considerations:

  • If the previous user on the machine is archived, as opposed to completely deleted, the UID will still be active and will conflict.
  • You should create a new user (UUUser), log out completely (not just switch users), then log in as UUUser, to perform this change. Then log out completely, log in as you.
  • IMHO, there is a serious risk of unintended consequences, and I am in no way going to test this solution. See my comment to your question. See here for detailed discussion.

I found one answer to my question at this archived page, which is old but still would probably still work. It involves rejiggering the new install to match the old TM UIDs. Unfortunately, in my current case the old TM UID is crazy-large (423890409). I don't know why, maybe something about my organization. But I haven't found any way to specify the UID while creating an account.

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