Ventura & Time Machine Disk Corrupted or Broken on Upgrade

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13 points

Ventura & Time Machine Disk Corrupted or Broken on Upgrade

I just upgraded to Ventura on a Mac Mini M1. I have an external SSD for Time Machine backups on USB-C and everything was working fine before the upgrade.

After the upgrade, I get an error "macOS can't repair the disk 'SSD backup'." I can still read from the drive, but not write.
When I check the Time Machine control panel and check the red "i", I get a dialog that tells me that the files can't be copied because the disk is read-only.
"Find Info" on the disk, shows that system and wheel are RW, everyone is Read-Only.
I know Ventura requires specific permission to talk to USB devices, but the dialog in security to "always allow" or "ask" etc. is missing. I thought that's where the setting is, but is it somewhere else?
Finally, I tried First Aid on the disk and got an error (-69845) saying that the operation failed.

Am I dealing with some kind of known issue? Short of reformatting or replacing my backup ssd, is there anything else to try? I really don't want to lose all the time machine history.

Mac mini 2018 or later

Posted on Oct 29, 2022 6:06 PM

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Answer 1

Nov 26, 2022 3:04 AM in response to dobrynin_video

No. Had to wipe the HD and start again.

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Answer 2

Dec 12, 2022 10:50 AM in response to mjdicqerson

I have the same issue on my 2019 MBPro. Just updated to Ventura and and Time Machine can't write to back up drive with 4+TB available space because: "The operation can’t be completed because you don’t have the necessary permission."

I cannot drag and drop onto it either. Sharing permissions are set to "Read and Write" for me, system and something called "wheel". If I try to make changes to those permissions I am told "The operation can’t be completed because you don’t have the necessary permission".

Like you, I really don't want to reformat my drive.

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Answer 3

mjdicqerson Author

Level 1

13 points

Dec 12, 2022 4:02 PM in response to mjdicqerson

I wound up reformatting the backup drive, but I noticed something interesting (which may not have any bearing on the problem). The external SSD was formatted "Mac OS Extended" before I reformatted it. When I went to reformat it, the only option available was APFS. My understanding is that Time Machine did not support APFS prior to Ventura but maybe something broke. The main volume on my Mini is formatted to APFS. I can't imagine that this is the expected behavior.

Maybe, check to see how your Time Machine volume is formatted and then we could report a pattern.

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