User profile for user: KoolKiwi
KoolKiwi Author
User level: Level 1
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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User profile for user: KimballLarsen
KimballLarsen
User level: Level 1
13 points

Posted on Nov 24, 2020 9:57 AM

Ok, I resolved the issue, and Time Machine is now backing up correctly.


To recap: This computer never had Catalina on it. Went straight from Mojave -> Big Sur. After upgrade to Big Sur, no Time Machine backups would work at all (to external USB hard drive or to a network store). They all failed with a message like "Time Machine could not back up the disk "%@" because a snapshot of the disk could not be created."


On the misbehaving machine, I had to remove the /Volumes/com.apple.TimeMachine.localsnapshots directory. This is a hidden directory, but you can delete it via the terminal if you have sudo or root permissions. I noted that in this directory were some snapshots from *before* Big Sur was installed.


sudo rm -r /Volumes/com.apple.TimeMachine.localsnapshots


Once that was deleted, I also deleted all the local snapshots using this terminal command (note that this listed and deleted snapshots from *after* Big Sur was installed: 


sudo tmutil deletelocalsnapshots /


As soon as I did both of the above, Time Machine started working correctly.

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User profile for user: KoolKiwi
KoolKiwi Author
User level: 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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User profile for user: TJMatson
TJMatson
User level: 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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Time Machine snapshot could not be created for the disk "%@"

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