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Time Machine error

jdw13 said:
I agree that CCC is excellent and I have been using it for years with scheduled backups to various destinations every day. However, I also use TimeMachine because the restore interface is so convenient to drill down and get an earlier version of a single file. If nightly fails, I let it backup when I wake the machine. I, too, have reported this to Apple and agree this is not worth any more effort especially when Apple ignores our feedback.
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I'm using both these days. Like you I find Time Machine a lot easier for quick restoration, and aside from the bug described in this thread I find it is pretty reliable. But CCC is very reliable and a bit more flexible, and also very fast. So I do this:
  1. Time Machine set to 1x/day interval
  2. a CCC copy of just my home directory I run every week (keep this backup lean so I can hopefully keep a very long history on the drive over time)
  3. a full CCC clone of *everything* I own once a month -- with the drive kept in my desk at work.
 
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New Mac OS 15.4. The same error just came up. It's ok though. Remember new Emoji for 15.4...thats super duper important to Apple.
 
Weird -- it stopped happening for me a couple of weeks ago, even though I hadn't changed anything. Now I'm afraid to update to 15.4!
 
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kirbyrun said:
Weird -- it stopped happening for me a couple of weeks ago, even though I hadn't changed anything. Now I'm afraid to update to 15.4!
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Yeah it goes for weeks without the issue, then suddenly it pops up a few times. Then it stops for a few weeks... it's really stupid and Apple doesn't care to fix it.
 
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Not sure precisely when it started, but in the past month or two, my 2019 Intel MBP on 15.4 will no longer backup to my Time Capsule. I've erased the disk a few times and started a fresh backup (since I have multiple other backups), and each time it completes the first full backup without a hitch, but starts to fail on the following incrementals.

The error message I get is simply "Backup not completed. Time Machine could not backup to "my time capsule"", with no further information.
 
Just an updated. 15.4.1 doesn't fix this issue. I never turn off my iMac and the screen does turn off. This morning that fun message came up. OH well.
 
I don't think Apple will fix this issue in Sequoia. If they fix it, it'll be in the next major OS release. With their yearly release schedule, they don't have time to fix a lot of bugs and so non-critical bugs persist for months and even years until they get around to eliminating them.
 
maxplanar said:
Not sure precisely when it started, but in the past month or two, my 2019 Intel MBP on 15.4 will no longer backup to my Time Capsule. I've erased the disk a few times and started a fresh backup (since I have multiple other backups), and each time it completes the first full backup without a hitch, but starts to fail on the following incrementals.

The error message I get is simply "Backup not completed. Time Machine could not backup to "my time capsule"", with no further information.
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I have two Time Capsules. They worked great in Sonoma and earlier, but Sequoia introduced this bug and Apple hasn't bothered to fix it.
 
Idgit said:
I don't think Apple will fix this issue in Sequoia. If they fix it, it'll be in the next major OS release. With their yearly release schedule, they don't have time to fix a lot of bugs and so non-critical bugs persist for months and even years until they get around to eliminating them.
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Very odd that Apple these days do not believe that successful Time Machine backups are critical for a consumer. Of course one should expect them to really care about these things.
 
kagharaht said:
Very odd that Apple these days do not believe that successful Time Machine backups are critical for a consumer. Of course one should expect them to really care about these things.
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You would think, right? But they clearly don't given that they haven't bothered to fix it.
 
kagharaht said:
Very odd that Apple these days do not believe that successful Time Machine backups are critical for a consumer. Of course one should expect them to really care about these things.
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There isn’t any problem making Time Machine backups as long as you aren’t trying to do it to a piece of equipment that was discontinued 7 years and 6 operating systems ago.
 
Daverich4 said:
There isn’t any problem making Time Machine backups as long as you aren’t trying to do it to a piece of equipment that was discontinued 7 years and 6 operating systems ago.
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iMac M3 Max configuration. MBA M2 15”. So it’s not an old Mac.
 
For quite a while I haven't had the problem since I'd excluded a problematic directory from the backups. The other day I had the problem again.

A simple log query reveals the locked files. I simply run "log show -last 8h | grep "Failed to acquire". It does take a very long time to finish, but it does show the files which are locked at the time of the backup. I pick "last 8 hours" since it happens overnight. But, a shorter time interval is possible if you look at the failure times in System Settings.

The latest incident involved a program that I almost never run. It's an iPad program that can run on my Mac. It's called "Eve" and it allows me to tweak some settings on my Eve Outdoor Camera. I ran it the other day and had the backup problem that night.

The log entries were all identical. Here's one line:

Code: 
2025-04-30 06:09:17.645479-0700 0x2efc98   Error 0x0 578 0 
backupd: (TimeMachine) [com.apple.TimeMachine:FileProtection]
Failed to acquire device lock assertion for
'/Volumes/com.apple.TimeMachine.localsnapshots/Backups.backupdb/m3/2025-04-30-060621
/Data/Users/xxx/Library/Containers/21694607-FEB9-4F63-BF7E-5EB0A9415704/Data/Library
/Saved Application State/com.elgato.eve~iosmac.savedState/data.data'
(assertion state: <dropped>), error: Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted"

I added a bunch of line breaks to make that readable. You can see that at the beginning of the backup, Time Machine took a snapshot of the disk and was backing that up rather than the working disk.

If you know the format of the log command and its output you can see that the error lines have

process = backupd
sender = TimeMachine
subsystem = com.apple.TimeMachine
category:FileProtection

You could use those if you wanted to query your own logs more efficiently. It might speed up getting the results:

Code: 
log show -last 8h --predicate 'process=="backupd"' | grep "Failed to acquire"
 
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svenmany said:
This thread is about backups failing because files aren't available on the Mac being backed up. I'm backing up to current generation, attached, SSDs. I encounter the problem.
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I was replying to a recent post about it not working correctly with Time Capsule. I use current backup drives for 3 Time Machine backups and all of them work correctly.
 
kagharaht said:
Very odd that Apple these days do not believe that successful Time Machine backups are critical for a consumer. Of course one should expect them to really care about these things.
Click to expand...

Is there a possibility that not all of the fellows who have experienced the error reported the bug to Apple through formal reporting? Apple does not read this forum.

The more we report bugs, the faster the fix.
 
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Idgit said:
I don't think Apple will fix this issue in Sequoia. If they fix it, it'll be in the next major OS release. With their yearly release schedule, they don't have time to fix a lot of bugs and so non-critical bugs persist for months and even years until they get around to eliminating them.
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I'm struck by your comment "they don't have time to fix a lot of bugs". I agree with your sentiment, but the not having enough time is a fallacy. They're in control of the time they have. It's a function of how much they want to spend hiring enough people. At least they recognized they've made a mess of the current Settings UI's and are saying they're borrowing the approach developed for visionOS. Let's hope it's more than a different UI built on top of old plumbing in need of attention.
 
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svenmany said:
To add to your thinking, consider:

en.wikipedia.org

The Mythical Man-Month - Wikipedia

en.wikipedia.org en.wikipedia.org
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Thank you. I hadn't seen that book. But based on my quick read of the Wikipedia article, it has a lot of truth. One that is really difficult is introducing "new" people to an ongoing project reduces productivity. However, the case in point in this thread is fixing bugs rather than starting from scratch. Finding bugs takes a lot of skill and experience and it's more difficult if the code in question has been stable and reliable for long enough that there may not be people who are familiar with the code, or that the problem occurs from interaction between unexpected relationships between components.
 
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