Time Machine couldn't complete backup

[donawalt]

There have been similar reports of this, I think it's a Sequoia bug but I am interested in investigating it if possible - twice now I have gotten "Time Machine couldn't complete backup..." since the upgrade to Sequoia. I never saw this before that.

Is there a way to find out what file(s) it's complaining about? I just let it run again on its own, and everything is fine. Both times it was overnight.

 

[EugW]

I am very occasionally getting this problem now on Sequoia on my M4 Mac mini. I did not have this problem with my M1 Mac mini before I switched to the M4. It's frustrating. However, it seems to happen only when my Mac is locked (as indicated by your screen grab). Backup works just fine if I'm working on the machine and the Mac is unlocked.

I tried wiping and reformatting my Time Machine drive (external USB 4 drive) but it made no difference. Note that I am backing up not only my internal drive, but also another external USB 4 data drive (not the Time Machine one).

Also, this may be coincidental, but I do note that it started happening after I moved my external USB 4 data drive to a Thunderbolt 4 / USB 4 hub. When it was connected directly to the Mac, I didn't encounter this error. Perhaps I will try directly connecting it to the Mac again to see if that changes anything. What is your setup?

 

[kagharaht]

Follow this thread.

https://forums.macrumors.com/threads/time-machine-error.2437741/