Time Machine couldn’t complete the backup to “My Book for Mac” after upgrade to Big Sur

[mafopinion]

Hello. Until this last Monday I was running my iMac on Mojave, upgraded from perhaps Sierra (??) before that. I'm running a Mid-2015 iMac and the external drive (MyBook for Mac) has backups back to 2016. Immediately upon upgrade to Big Sur I began to receive the Time Machine couldn't complete the backup message, with the only additional detail given being, "An error occurred while preparing the backup." Ran through the basics, External drive Disk Utility, Unmount/Mount, remove drive in TM preferences and reset. Apple Support had me run disk utility on all internal drives - no issues found. Apple support suggested reformatting backup disk (not doing that as my only backup) or buy new external disk (which I have awaiting opening). Found a suggestion at Apple boards to thin the local snapshots and delete the in-progress folder on external drive. Completed, but no change. Ran the log and all seems to start to go sideways at the following line:

Unrecoverable zero fileid - path: 'Users/XXXXXXX/Library/Containers/com.apple.Safari/Data/Library/Caches/com.apple.Safari/WebKitCache/Version 16/Blobs/97829D2F9B149F4B0DBD93B1D000E22F51831C81', flags: 00100200

(I have removed my user name and replaced with XXXXXXX, but otherwise this is a direct cut and paste). Quite a bit more log (attached as file), but I'm questioning how to proceed. If TM or another corrupt file is not going to allow a backup, it seems fruitless to open a new $180 backup drive (not sure it can be returned if attached/formatted). Or, perhaps new drive/fresh backup would solve the problem. Other than those two, seems like the options would be:

1.) Revert using the TM backup from right before I upgraded to Big Sur (which seemingly has it's own risks)
2.) Use something other than TM for backup (major disappointment).
3.) Take to the Apple store for evaluation.
4.) Some other plan, not currently evident.

I am way out over my ski's with this one - even using Terminal (for the snapshot thinning) was a nerve wracking experience. Really want to have the Restore from a TM backup functionality (frankly the reason I switch my entire household to the Apple ecosystem 12+ years ago), but not sure how to proceed.

Any suggestions/ideas would be most appreciated. Thanks.

 

[jz0309]

Hello. Until this last Monday I was running my iMac on Mojave, upgraded from perhaps Sierra (??) before that. I'm running a Mid-2015 iMac and the external drive (MyBook for Mac) has backups back to 2016. Immediately upon upgrade to Big Sur I began to receive the Time Machine couldn't complete the backup message, with the only additional detail given being, "An error occurred while preparing the backup." Ran through the basics, External drive Disk Utility, Unmount/Mount, remove drive in TM preferences and reset. Apple Support had me run disk utility on all internal drives - no issues found. Apple support suggested reformatting backup disk (not doing that as my only backup) or buy new external disk (which I have awaiting opening). Found a suggestion at Apple boards to thin the local snapshots and delete the in-progress folder on external drive. Completed, but no change. Ran the log and all seems to start to go sideways at the following line:

Unrecoverable zero fileid - path: 'Users/XXXXXXX/Library/Containers/com.apple.Safari/Data/Library/Caches/com.apple.Safari/WebKitCache/Version 16/Blobs/97829D2F9B149F4B0DBD93B1D000E22F51831C81', flags: 00100200

(I have removed my user name and replaced with XXXXXXX, but otherwise this is a direct cut and paste). Quite a bit more log (attached as file), but I'm questioning how to proceed. If TM or another corrupt file is not going to allow a backup, it seems fruitless to open a new $180 backup drive (not sure it can be returned if attached/formatted). Or, perhaps new drive/fresh backup would solve the problem. Other than those two, seems like the options would be:

1.) Revert using the TM backup from right before I upgraded to Big Sur (which seemingly has it's own risks)
2.) Use something other than TM for backup (major disappointment).
3.) Take to the Apple store for evaluation.
4.) Some other plan, not currently evident.

I am way out over my ski's with this one - even using Terminal (for the snapshot thinning) was a nerve wracking experience. Really want to have the Restore from a TM backup functionality (frankly the reason I switch my entire household to the Apple ecosystem 12+ years ago), but not sure how to proceed.

Any suggestions/ideas would be most appreciated. Thanks.

there are multiple threads here with Time Machine related issues in Big Sur, posted below.

So you still have all your data, correct? you just want to make sure that your backup is capable of restoring just in case?
Have you run FirstAid in Disk Utility? you don't mention it it in your post but you might have ...
After you deleted the in-progress folder on the HDD , did you re-boot?

I'm not sure that I can provide much more help, I spent week trying to figure out what was going on (it's pretty much all documented in-between those 3 threads below) and I have given up on Time Machine. I am now using Carbon Copy Cloner and am very pleased with it, and I strongly suggest you have more than 1 backup going forward ...

Big Sur 11.5.2 ruining Time Machine HDs?
Do you have Time Machine HD failures with Big Sur 11.5.2?
2 external HDDs failing AFTER Big Sur upgrade?? or?

 

[mafopinion]

there are multiple threads here with Time Machine related issues in Big Sur, posted below.

So you still have all your data, correct? you just want to make sure that your backup is capable of restoring just in case?
Have you run FirstAid in Disk Utility? you don't mention it it in your post but you might have ...
After you deleted the in-progress folder on the HDD , did you re-boot?

I'm not sure that I can provide much more help, I spent week trying to figure out what was going on (it's pretty much all documented in-between those 3 threads below) and I have given up on Time Machine. I am now using Carbon Copy Cloner and am very pleased with it, and I strongly suggest you have more than 1 backup going forward ...

Big Sur 11.5.2 ruining Time Machine HDs?
Do you have Time Machine HD failures with Big Sur 11.5.2?
2 external HDDs failing AFTER Big Sur upgrade?? or?

Thank you for the response. I did see those posts, but I don't believe the HD has failed. I did run Disk Utility/First Aid, with no issues reported. Also, I can enter Time Machine and see the previous backups all the way back to 2016. The last backup is the one right before I upgraded to Big Sur. I do have data backed up via Google Drive, Backblaze, and iCloud for photos. Nevertheless, I have had total system failures before and like to be able to use the restore from backup functionality, putting everything back as it was, without having to download everything from the cloud. Thanks for your help and the links. I will look into Carbon Copy Cloner. Thank you!

 

[chscag]

Your choice of course, but I have to ask: Why keep TM backups from 2016? Is there some reason for doing so?

Generally, TM backups older than 6 months to a year are usually no longer applicable or obsolete due to updates in apps and macOS.

And I agree with the previous reply about running First Aid on your TM drive.

 

[jz0309]

Thank you for the response. I did see those posts, but I don't believe the HD has failed. I did run Disk Utility/First Aid, with no issues reported. Also, I can enter Time Machine and see the previous backups all the way back to 2016. The last backup is the one right before I upgraded to Big Sur. I do have data backed up via Google Drive, Backblaze, and iCloud for photos. Nevertheless, I have had total system failures before and like to be able to use the restore from backup functionality, putting everything back as it was, without having to download everything from the cloud. Thanks for your help and the links. I will look into Carbon Copy Cloner. Thank you!

Since you have a new HDD, my suggestion is that you use CCC, they have a 30 day free trial, test it out to see if it meets your needs.
Meanwhile, I’d contact Apple again and tell them that you need to restore files from that TM backup and make sure it gets escalated to a senior adviser…

 

[george_i]

It seems that the Time Machine preference file is corrupted. Please follow the instructions, the file will be replaced by a new one and the following backup will be added to the existing ones.

1.In the TM interface uncheck the box "Back Up Automatically".

2. Go to /Library/Preferences and move to the bin the file com.apple.TimeMachine.plist (authentication needed).

3. Check the box "Back Up Automatically".

4. Select the backup disk.

5. A new backup will start.

 

[mafopinion]

It seems that the Time Machine preference file is corrupted. Please follow the instructions, the file will be replaced by a new one and the following backup will be added to the existing ones.

1.In the TM interface uncheck the box "Back Up Automatically".

2. Go to /Library/Preferences and move to the bin the file com.apple.TimeMachine.plist (authentication needed).

3. Check the box "Back Up Automatically".

4. Select the backup disk.

5. A new backup will start.

Thanks for the input. Just tried this, but unfortunately the same error after a short attempt at preparing the backup. I appreciate the effort in the attempt!

 

[mafopinion]

Since you have a new HDD, my suggestion is that you use CCC, they have a 30 day free trial, test it out to see if it meets your needs.
Meanwhile, I’d contact Apple again and tell them that you need to restore files from that TM backup and make sure it gets escalated to a senior adviser…

Thanks for the thoughts. I think this is good plan. I've been looking at CCC and it seems like a good alternative. I really did not know that you could use migration assistant with a third party program (when setting up a new Mac) or restore from a third party backup. TM has worked for me all these years, so I appreciate the input and information.

 

[george_i]

What exactly is mentioned as the cause of the error ?.

 

[mafopinion]

Thanks for the follow-up. The only detail when the box pops up is: "An error occurred while preparing the backup." Nothing else. I did attach the Log report that I ran following the failed backup. Not sure if that will help. This is the most frustrating thing about the error. There's not much information and no specific error number or anything like that. Thanks for your help.

 

[george_i]

According to the report, Spotlight seems to be the main culprit for the issue.
Let's try to exclude the Time Machine disk from indexing.

1. In System Preferences open Spotlight.
2. Drag the TM disk icon to the Privacy window.
3. Click on it an and click the minus sign on the bottom to remove it (you may be asked to authenticate), so that the disk is not further indexed.

Any luck ?

 

[Eduardot]

 

[mafopinion]

According to the report, Spotlight seems to be the main culprit for the issue.
Let's try to exclude the Time Machine disk from indexing.

1. In System Preferences open Spotlight.
2. Drag the TM disk icon to the Privacy window.
3. Click on it an and click the minus sign on the bottom to remove it (you may be asked to authenticate), so that the disk is not further indexed.

Any luck ?

Sorry, have been away for a few days. I tried this procedure but received the same error message. Just for clarification, I added the disk and then pressed (-) before trying the backup. Was I supposed to try the backup in between step 2 and 3? After step 3 the icon disappeared and the box appeared as it had in Step 1. Thanks.