What causes Time Machine to stall during backups?

Another update guys.... since updating the firmware on the Nanoleaf lightstrip the 'Tile' on the iPhone has stopped giving any error messages and is working perfectly. So yesterday I put the Home widget back on the Mac desktop and configured it only to show the lightstrip and a smart plug.

So far the TM backups have been completing with the Mac locked or unlocked with the Home widget in place. I've done a lot of backup tests (Mac manually or automatically locked).

TM has been working flawlessly for 3 days, 23 hr, 40 min, and good since the Home widget was put back on the desktop 15 hr, 54 min ago.

It is still early days and I'll continue to monitor.

It is interesting to note though that my wife has had the same TM backup issues on her iMac, with the errors hitting her daily. I did reset her TM backup a couple of days ago but typically that only helped for a day or two. Since updating that firmware she has not had the TM backup error either. It could be pure coincidence but......

It does seem to make me think that it could be logical that (in my case at least):

• The Nanoleaf firmware being out of date was causing an issue within HomeKit
• That Homekit issue was common to the network and hence affected my wife's machine.
• Resolving that issue fixed the problem on both machines.

So do you guys have any Nanoleaf (or other) products sat in your Homekit systems where firmware needs updating? It might be worth checking.

As always any feedback appreciated.

The latest things I'm trying:

• Emptied the Trash Can
• Rebooted the Mac
• Wiped and formatted my TM backup drives (emptied the NAS TM share)
• Set TM up to backup to external drives only (for now I've ignored the NAS share as it's slower)
• [Still got the TM errors up to here]
• Forced a Spotlight reindex (again)
• Went into TM settings and excluded all external drives from the Backup
• Went into Spotlight Privacy and excluded all external drives as well as network shares from being searched.

So far four TM backups with the Mac locked with no issues.

When you reformat your external drives, do you let Time Machine format the drives for you? I remember formatting this way just before my TM backups started working. Make sure your format is APFS Case-Sensitive, because I was formatting manually using non case sensitive APFS, until TM formatted my drive for me. To do this, remove your drive in TM settings, (it will not delete your contents at this point) then restart Mac and re-select your drive for backups. Very quickly, your drive will come back online formatted and ready to go, but of course, your previous data will be erased. My TM is still working this morning. Hope this helps.

To add the exclusion on my system I had to do the following in a Terminal session with Full Disk Access enabled:

sudo tmutil addexclusion -p ~/Library/Containers/com.apple.findmy.FindMyWidgetItems/Data/SystemData/com.apple.chrono/snapshots

That isn’t what I posted. You need to get spotlight to reindex.

to do this add the main hard drive to the Spotlight ignore list, wait maybe 30 seconds and then remove it. This will start Spotlight reindexing on the drive.

You should be able then to check this by opening Finder and viewing most recents, you should see that list starting to populate.

Once that is there TM backups should now work with the Mac locked.

If your backups are screwed you may need to reinitiate them. Hopefully though you should be good after that is done.

To update....... the issue was still there with 15.3 .....

After a number of weeks with me updating Apple Support with things I'd tried (which worked for a while) and then failed again ..... and getting no reply back at all. I went through the pain of calling them again and complaining about the lack of a response.

Finally, I got it bumped to a 'new' top level support guy.....

He investigated, said it wasn't a confirmed issue, but did say to triage it further was I in a position to wipe the TM backup drives, wipe the Mac Mini and rebuild it manually (no TM restore).

As I'm retired that would be painful but not impossible to do. I'm now at the stage the Mac has been rebuilt, most of my essential apps are loaded, a new TM backup has been set......

So far it's all been running 5 days, 4 hours, with not a single TM backup problem.

I'm continuing to add apps daily, and I'm logging the install times of each, just in case the problem returns after an app is added in.

Anyway I thought you guys might appreciate the update. I'll keep everyone posted.

I just reported the defect you see with 15.1 and the one I saw with 15.0.1 with Apple Support. If you do, they will give you a case ID number and you can inquire with them when an update comes if it addresses the issue using the case ID number.

I am sorry to hear that the solution was to wipe out your hard drive and restore from a previous backup. So, I guess that you are now back in 15.0 which showed no issues with TM for me.

It's still good for me. After reinitialising Spotlight it failed once (after about 11 days) and immediately I put in the Find My folder exclusion. Since that was done it has been completely solid with no failures at all.

The only other thing I've done was remove the backup to the NAS and now just backup to the hard drives. This was done as I found the NAS slowed down too much when backups ran at the same time on my Mac and my wife's.

She backs up to the NAS with the FindMy fix in place and again has not had any issues since I put it in place.

15.3 Didn't fix the issue no, but as I said in the other post removing the Notes and Home widgets from the desktop seem to have made a difference. Since removing them I've not had a single TM backup problem.

Early days yet and I'm still monitoring but it's a good indicator.

It makes me wonder how many of you having the problem are using desktop widgets and if you are which ones?

I'm now using Apple Weather, Clock and third party Countdowns widgets with no problems.

So has anyone else tried installing the OS 15.1.1 update? I did, and TM is working for two days now.

Guys yesterday I realised that Spotlight was not indexing things properly on my Mac. I then followed this support article, and added / removed the hard drive on the Mac as well as excepting a few drives.

This morning I accessed the Mac and I had no TM backup errors at all. W00t!

So is it worth you guys reinitialising Spotlight and seeing if it fixes your errors? Worth a try!

I'm very sad to say that the problem has returned for me (again). I've forced a Spotlight re-index (again), and so far it seems to have fixed the issue. I've fed back on my ticket with Apple that the issue is back.

Update: My success backing up using Carbon Copy Cloner for one drive and TM for another with the TM backups set to proceed 1 minute after the CCC backups was short lived. The TM backups reverted to their old, "Can't complete the backup...blah, blah, blah" message a day later.

So, I have totally abandoned TM as a backup tool and now use Carbon Copy Cloner 7 for both of my backup drives and it performs perfectly. As I said in a previous message, I hold out no hope that Apple will solve this problem and consider the $30 spent to update my version of CCC well worth the money in terms of performance and peace of mind.

Third party backup issues were resolved in 15.3, maybe fixes are in there for TM too. It should be noted on my wife's iMac she had the TM backup issue, and none at all since upgrading to 15.3 (with a new external drive).

Have you tried reindenting Spotlight as I advised up thread? It solved the issue instantly for myself and my wife?