Time Machine snapshot could not be created for the disk "%@"

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11 points

Time Machine snapshot could not be created for the disk "%@"

I just upgraded my iMac (Retina 5K, 27-inch, Late 2014) to Big Sur. All went well, except Time Machine now will no longer create a backup.

I get the error: "Time Machine could not back up the disk "%@" because a snapshot of the disk could not be created."

I have about 87GB free on my single 1TB Fusion Drive.

After some googling, I have tried:

a. Run Disk Utility First Aid on the Fusion Drive (and again on the contained volumes - no issues).

b. Deleted old local snapshots - to free up space (tmutil listlocalsnapshots / etc.).

c. Confirmed I could manually create a new snapshot (tmutil snapshot).

d. Tried using a new Time Machine backup disk (no difference, as I assume the issue is happening before it actually backs up to the backup disk itself).

I suspect the key to the problem is the disk "%@" that Time Machine is apparnetly trying to create a snapshot of.

What is disk "%@" ? It sounds like a bogus disk reference? (which might explain why a snapshot could not be created).

I'm not sure what to try next?

Posted on Nov 17, 2020 12:12 PM

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Answer 1

Nov 30, 2020 2:26 AM in response to Natedogg33

If you're using Western Digital or SanDisk drives, download and install the latest WD Discovery suite. Reboot (this is essential) and then connect each drive. Make sure UAS is OFF for each (gear icon next to the drive). Eject, and reconnect. Problem should be solved. It solved it for my WD SSD Passport external drives. Flying once again, no beach-balls, no crashing with scary data loss messages. You might need to reformat a Time Machine to get it to be stable in backing up (APFS format with GUID partitions, encrypted too if you want to keep it secure). Hope this helps!

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Answer 2

KoolKiwi Author

Level 1

11 points

Nov 30, 2020 9:03 AM in response to Darren Hatch

@Darren Hatch. As noted earlier, the reported error is during the creation of the disk snapshot of your internal drive, *on* your internal drive. ie. Before backup data is written to your external Time Machine backup drive. Changing your Time Machine backup disk and/or reformatting it, is not where the problem lies. The problem is with the creation of a snapshot of, and on, your internal Mac OS drive.

An apparent solution to the snapshot permissions (that appear to be the root cause) has been posted above. I'm just not able to verify the posted solution for myself, as I'd already resolved my issue via the clean install procedure (that I also posted earlier).

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Answer 3

Dec 2, 2020 5:37 PM in response to KimballLarsen

Somebody get @KimballLarsen a medal! I've been living with this for a month just waiting for a smartypants to find a fix. Running those two terminal commands fixed the issue immediately. This should be posted more places. Seems like it's a common issue with the Big Sur update.

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Answer 4

Dec 3, 2020 12:12 AM in response to KimballLarsen

@KimballLarsen

I only had to go to the folder [menu Go>Go To Folder… "/Volumes"] and remove com.apple.TimeMachine.localsnapshots. Then kick a manual "Back up now" [and wait with silly bouncing bar for about half an hour] then back up started. Of course now it's big and claiming near a day…

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Answer 5

KoolKiwi Author

Level 1

11 points

Dec 17, 2020 11:42 AM in response to Tim Schlack

Hi Tim. I also upgraded to 11.1 yesterday, and I can report that my TM Backups are still working fine. However, in my case I had resolved the original issue via a clean Bug Sur install. I was hopeful that Apple had fixed the original Big Sur upgrade TM issue with this release.

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Answer 6

KoolKiwi Author

Level 1

11 points

Jan 4, 2021 2:44 PM in response to mbmitt

@mbmitt So are you seriosusly saying that even the solution I took (posted earlier) of a complete clean Big Sur installation didn't even work for you? If so, did you follow the procedure I outlined to ensure a full disk erase, clean install, and then data recovery.

If you instead only tried the other solutions posted (without any success), then please post what your steps were, so that someone can assist you with where it might have gone wrong. Hopefully someone can get this issue resolved for you also.

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Answer 7

Jan 4, 2021 3:14 PM in response to mbmitt

The terminal commands I posted above to remove the old TM backups from prior versions of the OS should have done the trick. If not, then the complete disk erase and clean install described by @KoolKiwi *will* definitely fix the problem (though it's quite a bit more work to do).

Did you get any error messages when you tried the solutions posted above?

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Answer 8

mbmitt

Level 1

4 points

Jan 4, 2021 3:22 PM in response to KimballLarsen

Yea, the terminal codes didn't work. Received no errors when during the terminal command, so I was hoping that would have done the fix.

I haven't gone through the steps of performing a backup and system wipe of my laptop. Just can't do that during the week.

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Answer 9

KoolKiwi Author

Level 1

11 points

Jan 4, 2021 3:26 PM in response to KimballLarsen

Yes, just to reiterate, I did the complete clean Big Sur install prior to @KimballLarsen's quick Terminal commands solution. So, unless there is an absolute need to, I'd just focus on the terminal commands solution. :)

However, for me at least, I'm happy I proceeded with the clean re-install approach as I also obtained the benefit of a significant performance boost (which I'd account for having never done a clean install previously, after many years and many OS release upgrades). Of course, YMMV!

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Answer 10

mbmitt

Level 1

4 points

Jan 5, 2021 10:44 AM in response to KoolKiwi

Found a new fix - without having to wipe your existing computer ;-)

You need to wipe out the external backup drive using APFS. If you want to use the external drive to backup multiple computers, you need to create individual volumes for each backup on the external drive.

Now the issue is Airport Time Capsules. Looking for a way to format the TC to APFS. I tried a factory wipe, but that didn't help.

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Answer 11

TJMatson

Level 1

4 points

Jan 24, 2021 2:51 PM in response to KimballLarsen

I am having the same problem where I am trying to backup using Time Machine and getting a message that "Time Machine could not create a local snapshot to back up from"; however, I am running Catalina and I cannot update to Big Sur because my disk is almost full. I tried the fix from KimballLarsen, but I got messages on terminal saying the files didn't exist. Does anyone have a fix for people experiencing issues with Time Machine on Catalina?

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Answer 12

Jan 25, 2021 9:32 AM in response to TJMatson

Hey TJMatson - what happens when you run this command in a terminal?

sudo tmutil deletelocalsnapshots /

Any error messages from that? If it runs successfully, then try rebooting the computer to get it to actually free up the space. If that does not work, go into TimeMachine preferences and turn off automatic backups, then wait about an hour to see if your free disk space increases.

Ultimately, though, you may need to move some data off your drive to free up enough space for both TimeMachine to do its thing and for the upgrade from Catalina to Big Sur.

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