Time Machine backups just stop

exoriare

macrumors member
Original poster
Oct 25, 2006
69
1
London
Hi All,

Late 2010 MacBook Air running High Sierra.

For years I have run two TM backups, one to a Time Capsule over wifi and one to an external HD connected through USB.

About a month ago both stopped running backups. The last back up on both of the two drives was on the same date. The TM menu item gives that date as the last backup for both drives but also says (correctly) that the next one is scheduled within the hour.

When the backups run they both go through the 'preparing back up' stage and then start backing up, but very slowly (KBs at a time). Gradually they pick up speed and back up about 5-10 Mb then just stop, as though I had aborted. The TM menu just gives the next scheduled backup time as though the last one had been successful, but the last one is still recorded as a month ago.

I have verified the Time Capsule backup (no problem) and I have tried running a TM backup on each drive separately, having removed the other as a backup disk.

Something seems to have happened at the point when the last backups ran on each drive, but I am at a loss as to what else to try.

Would be grateful for any suggestions.

Thanks
 

Soba

macrumors 6502
May 28, 2003
261
285
Rochester, NY
Hi All,

Late 2010 MacBook Air running High Sierra.

For years I have run two TM backups, one to a Time Capsule over wifi and one to an external HD connected through USB.

About a month ago both stopped running backups. The last back up on both of the two drives was on the same date. The TM menu item gives that date as the last backup for both drives but also says (correctly) that the next one is scheduled within the hour.

When the backups run they both go through the 'preparing back up' stage and then start backing up, but very slowly (KBs at a time). Gradually they pick up speed and back up about 5-10 Mb then just stop, as though I had aborted. The TM menu just gives the next scheduled backup time as though the last one had been successful, but the last one is still recorded as a month ago.

I have verified the Time Capsule backup (no problem) and I have tried running a TM backup on each drive separately, having removed the other as a backup disk.

Something seems to have happened at the point when the last backups ran on each drive, but I am at a loss as to what else to try.

Would be grateful for any suggestions.

Thanks
There is a small diagnostic program called The Time Machine Mechanic and I'm curious what it has to say about your backup history. Can you try downloading it from this page and running it? Please post back with all the messages it displays.

 

exoriare

macrumors member
Original poster
Oct 25, 2006
69
1
London
Thanks for your speedy reply Soba.

I ran the app to cover the last 48 hours, which seems to be the maximum. It has picked up errors, but understanding what they mean or what to do about them is beyond me. Hoping you might have further advice....


Analysis from 2019-12-25 08:31:49 +0000 to 2019-12-27 08:31:49 +0000 for 48 hours:
Backing up to /dev/disk2s2: /Volumes/Time Machine Backups/Backups.backupdb
Backing up to /dev/disk3s4: /Volumes/Time Machine/Backups.backupdb
on which there were 983.01 GB, 982.4 GB, 982.36 GB, 223.05 GB, 222.71 GB, 222.69 GB, 974.63 GB, 222.68 GB, 974.58 GB, 222.67 GB, 974.53 GB available.
Started 18 auto backups, and 5 manual backups; no backup has been completed successfully in the period,
currently still making an auto backup,
last manual backup started 1103.4 minutes ago,
backed up a total of 28343 files, range 25 to 6100 in each backup,
total data for each backup was 1 KB, 21 MB, 393 KB, 362.3 MB, 5.7 MB, 4.9 MB, 20.6 MB, 491 KB, 16.9 MB, 738 KB, 20.6 MB.
Created 0 new backups, and deleted 0 old backups,
Created 15 new snapshots, and deleted 1 old snapshots,
completed 1 deep traversal scans,
cancelled 12 backups.
4 errors reported:
2019-12-25 13:12:39.500541+0000 Error: (-43) SrcErr:YES Copying /Volumes/com.apple.TimeMachine.localsnapshots/Backups.backupdb/Susie’s MacBook Air/2019-12-25-125524/Macintosh HD/System/Library/CoreServices/Software Update.app/Contents/Resources to (null)
2019-12-26 09:16:59.126644+0000 Error: (-43) SrcErr:YES Copying /Volumes/com.apple.TimeMachine.localsnapshots/Backups.backupdb/Susie’s MacBook Air/2019-12-26-090428/Macintosh HD/System/Library/CoreServices/Finder.app/Contents/Resources/fi.lproj to (null)
2019-12-26 09:16:59.165475+0000 Error: (-43) SrcErr:YES Copying /Volumes/com.apple.TimeMachine.localsnapshots/Backups.backupdb/Susie’s MacBook Air/2019-12-26-090428/Macintosh HD/System/Library/CoreServices/Finder.app/Contents/Resources to (null)
2019-12-26 18:54:12.924861+0000 Error: (-43) SrcErr:YES Copying /Volumes/com.apple.TimeMachine.localsnapshots/Backups.backupdb/Susie’s MacBook Air/2019-12-26-184504/Macintosh HD/System/Library/CoreServices/Finder.app/Contents/Resources/French.lproj to (null)
 

exoriare

macrumors member
Original poster
Oct 25, 2006
69
1
London
Thanks - I could do that, but given that I've got problems with two independent backups on two different media I've been assuming that the problem didn't lie with the backups but the software producing the backups. Do you have reason to think that wiping the backup and starting over would solve the problem? Or is it just to see if it's a fix?
 

Soba

macrumors 6502
May 28, 2003
261
285
Rochester, NY
Thanks - I could do that, but given that I've got problems with two independent backups on two different media I've been assuming that the problem didn't lie with the backups but the software producing the backups. Do you have reason to think that wiping the backup and starting over would solve the problem? Or is it just to see if it's a fix?
My thoughts, exactly. From the error messages you posted above, I suspect you have a problem with the SSD in your Macbook Air. Let's start with that and see what we find.

You should run First Aid using Disk Utility to check both your internal SSD and the Time Machine drive. Disconnect any other drive (except Time Machine) from your system before doing this.

  1. Open Disk Utility from the Applications > Utilities folder.
  2. In Disk Utility, open the View menu and choose "Show All Devices."
  3. In the left column of Disk Utility, you will see a list/hierarchy, probably showing 4 drives. Select the first entry in the list and then click the First Aid button in the toolbar. Confirm that you want to run it and let it run.
  4. As it's running, click the small disclosure triangle that says "Show Details" and it will show a log with all the steps of what First Aid is doing. After First Aid finishes, please select all of these and then copy and paste them here (or into a temporary document on your Mac first just to consolidate them before posting here) so we can see the results.
  5. Repeat step 4 for all four drives in the list. Your Time Machine drive might take a while to run, so be patient and let it run uninterrupted to completion.

If a drive is good, it will show that it "appears to be OK" in green text at the end of the log. If there is a problem, it will usually say so in red text.

If First Aid reports that your SSD has a problem, you will not be able to repair it while the system is booted. You will need to repair it by starting from the macOS Recovery partition.

To do so:

  1. Restart the Mac, then immediately hold Cmd+R after you hear the system startup chime. This will take you into macOS Recovery and present you with a screen with several options, including the last entry in the list that allows you to run Disk Utility.
  2. Choose Disk Utility from this screen and then run First Aid on your SSD as you did before.

You won't be able to copy paste while in Recovery mode, so if the First Aid log still shows an error, please try to take photos of the screen and share them here.

Restart your Mac normally when First Aid is completed.

Let us know how this goes.
 
Last edited:

exoriare

macrumors member
Original poster
Oct 25, 2006
69
1
London
I have spent most of the day in this and may have cracked it, but have no real idea how.

I did all you suggested and there were no problems reported. In fact I booted up from an external drive but no repairs were necessary. Everything got the big green tick.

I then tried removing both of the drives from the TM list and restarting the Mac. I then just added the external drive (not the Time Capsule). The TM window said there were no existing backups. I then ran a backup but it just repeated the old problem, apparently backing up just a few MB and then stopping. Then the TM window recorded the last successful backup as a month ago, as before.

I don't know why but on a hunch I then re-ran the backup to the same drive and it worked! Repeated and it worked again. Backing up to this drive now seems to be reliable

I then removed that drive and tried the same with the Time Capsule. That backed up about 90% and then stopped. To date I have not been successful with this one.

But I managed to borrow another external drive, reformatted it and ran a back up, which failed with the usual problem. I ran it again and this time it worked. I have now run repeated backups on it and it seems reliable.

I am now trying yet again with the Time Capsule drive overnight and if this doesn't work I may try deleting the backup and trying again, as I now have two other apparently reliable backups.

I have a feeling this may have something to do with the snapshots, but I don't now enough about them to be sure of this.
 

Soba

macrumors 6502
May 28, 2003
261
285
Rochester, NY
I have a feeling this may have something to do with the snapshots, but I don't now enough about them to be sure of this.
I was expecting some kind of filesystem corruption affecting the local snapshots, but perhaps it's the snapshots themselves that are problematic.

You can try deleting the local snapshots. There used to be a Terminal command to disable local snapshots and delete all of the existing ones simultaneously, but it looks like this was removed in High Sierra.

You can browse through and delete them one at a time using Terminal. Open Terminal and type:

Bash:
tmutil listlocalsnapshots /
The Terminal should show a list of local snapshots.

To remove a snapshot:

Bash:
sudo tmutil deletelocalsnapshots date
where "date" is the date and time stamp of the snapshot, which you saw in the output of the first command. Terminal prompts you for your password and will then delete the snapshot. Repeat this command for every snapshot and see if this makes things any more reliable.

If there are many, many snapshots and they are onerous to delete, I'd try starting with the four that TimeMachineMechanic reported as problematic and see if that helps.
- - Post merged: - -

 

exoriare

macrumors member
Original poster
Oct 25, 2006
69
1
London
The Time Capsule backup finally 'took' after a couple of attempts. I then hooked up both drives again and so far they seem to be working together fine now. I was going to delete the snapshots, just to tidy up, but all previous snapshots except for the three most recent seem to have been wiped anyway. In case anybody has a similar issue I'm still not sure exactly what solved it, but I hope there are enough details here to try what I did.

Time Machine Mechanic is now showing no errors - thanks Soba.
 
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