Suddenly, Time Machine won't backup

Question

denis9009 Author

Level 1

22 points

Suddenly, Time Machine won't backup

Hi all!

This is really strange. I just bought a new (used) iMac. I restored my

hard drive content on the new computer, with a Time Machine backup, and

it all went fine. High Sierra OS.

Now that I'm on my new iMac, and Time Machine won't make backups. I'm

mentioning that it doesn't seem to be a hard drive problem, because I

have two Time Machine backup hard drives, and it doesn't work with

neither of them.

As a hard drive problem was my only lead, I tried everything I found on

the Web (repair and others). Nothing worked. The last solution: format

the drive. It still doesn't work.

I'm clueless here. Any ideas?

Thanks a lot!

iMac 27″ 5K, macOS 10.13

Posted on Nov 29, 2020 9:58 AM

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Answer 1

Old Toad

Level 10

210,615 points

Nov 29, 2020 3:20 PM in response to denis9009

Boot into Safe Mode by booting with the Shift key held down and try a backup from there. Reboot normally and try again.

NOTE: Safe Mode boot can take up to 10 minutes as it's doing the following;

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts

• Deletes font caches, kernel cache, and other system cache files

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Answer 2

denis9009 Author

Level 1

22 points

Nov 30, 2020 9:33 AM in response to Old Toad

Thanks a lot for trying to help!

I did what you told me, and the boot drive was fine.

Finally, it works now, after I did these two things (update to Mojave and delete the "data HD" that was left as a result of a previous Catalina install). I think that it is the deletion of the "data HD" that did the thing, because right after the Mojave install restart, I tried Time Machine and it was not working.

Actually, the guy sold it to me with Catalina installed, but as I didn't want to have to cope with application incompatibilities, I went into Recovery Mode, erased the Macintosh HD and installed my last Time Machine backup (on the HD that was not named "data").

I'm happy it's solved... the solution of that kind of problem is not always easy to find (when it's obvious, the solution is easy to find).

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Answer 3

Old Toad

Level 10

210,615 points

Nov 29, 2020 4:38 PM in response to denis9009

So you've tried other disks for Time Machine and get the same problem? Then I'd boot into the Recovery volume (boot with the Command + R keys held down), select Disk Utility and run Disk First Aid on your boot drive. If you get an error message rerun DFA until there's no errors detected. The reboot and try backing up again.

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