What causes Time Machine to stall during backups?

It's just lazy customer support to ask users to wipe their TM drive and/or Mac hard drives (and restore or reinstall macOS). There is obviously a NEW bug in macOS 15 that is causing this when TM kicks off and the screen is locked. Obviously. Wiping everything only papers over the problem and DOES NOTHING to find the real issue.

I say "lazy" without any guilt. I do customer support for a software company and I always want to find the real cause rather than paper over it. Look how many people are impacted by this!!! The real number is 1 or 2 orders of magnitude more! (because people don't spend the time finding a place to post their problem)

The 'issue' came back for me this morning. So instead of my usual 'fix routine' (emptying the trash can and reindexing Spotlight) I've added your exception and we'll see if it fixes it!

Fingers crossed!

I just added the M4 Mac mini to my NAS backups and I am getting the same issue with 15.2. Tried all the solutions here and the issue comes right back. I have a M2 MacBook Air that uses TM to the same NAS and it has no issues, settings are the same so not sure what the issue is. Backups are too important for me, unless Apple fixes this issue I'm going to be using an alternative to TM (most likely Arq) just to much time wasted trying to work around these issues. Starting to feel like a windows user.

with your experience, i can't say that i blame you for not trusting the backup. however, every time i've needed to recover a file or file system, the backup was there. now you've got me scared. thanks for nothing :-) (that's supposed to be a smiley face). after taking part in this discussion, i'm going to have an alternate backup system ready to go.

I also have a Mac Mini M4, a MacBook Air, and an M1 mini and Time Machine (Sequaoia 15.2) used to have the problems mentioned in this thread, but I did something suggested in the thread and it fixed it. Unfortuately I can't remember what it was but it was on this thread.

Hi bruiselee 13! This looks very cool! Thank you for sharing. And I hope you enjoy your new monitors!!! If my guess at when TM schedules my daily backups is wrong, I will check this out. BTW, maybe it's just my computer, but the posts in this discussion thread are chronologically all over the place. Your December 30th post about "timemachineeditor" was put on page 2 of this 6 page discussion. The next post is from Nov. 3rd! Maybe I have some setting all janked up. But if not, something crazy is going on here. Perhaps the discussion about Time Machine has morphed into one about Time TRAVEL. 😂

hi mr. luigi. i've read all of your postings, but i'm just going to respond to this one. ccc sounds like a good solution and i'm going to keep it in mind if/when my backups start failing again. as for this group's timeline? i see the same sort of page/response arrangement. it looks like they're using a scatter algorithm to "sort" the responses. finally, my two displays work great except another problem re-reared its head. (this was a problem that i believe was fixed and is once again broken.) when the displays wake up from being asleep, all the windows migrate to the primary display. so i have to drag them all back. i wrote a black screen saver and never allow my displays to sleep. sad. oh, i have six workspaces spread over the two displays. lots of fun.

Hi bruiselee, old friend!

Sorry to hear about your displays. I have two 4K displays in my setup and sometimes when I log-in the main display fails to "activate." I have to unplug its connector to my 2018 Mac Mini and plug it back in and that solves the problem. Other times the screens that were on one monitor reappear on the other monitor when I log in and the secondary display becomes the main display. This doesn't happen often, so I just live with it. But I thought I would mention it since you shared your own experience with your displays. CCC continues to perform like a dream. It is such a relief to not have to deal with TM backup problems anymore. Especially since the M4 Mac Mini that has the problem was a Christmas Present from me to my wife and I wanted her to have a fun and smooth experience with her new machine. The last thing I wanted was for her to have me constantly on HER Mini trying to solve the TM issue. As I read the posts here about the problems people continue to have with TM, it makes me wish I was infinitely wealthy so I could gift them a license to Carbon Copy Cloner so they could be done with the problem and enjoy their computers. Too bad CCC hasn't seen this discussion thread. If they had, I think it would be smart business for them to offer everyone a discount to CCC 7 using the coupon code, "TimeMachineWillDriveYouMad." 🤣🤣🤣 Cheers, Luigi

fortunately for me i didn't have to spend a lot of time getting a solution that worked for me. but it was a stressful day and a half. i needed that backup to work. now. you can't possibly know i'm old :-) my wife once gave me a garage door opener for christmas. it was for a house that should never have had an automatic opener and it took me all day to install it (it would close, but bounce back open). the upside? her father, a very accomplished handyman, came over to help. he said there's nothing for it except to hew out the beam to make room for the travel rod. i looked at it and said to myself, hey that's a right triangle. if i only knew the Pythagorean theorem, i could resolve this issue without a single hew. fortunately, i know that theorem and solved the problem in 5 minutes by lowering the control unit to make the travel rod the length it needed to be. i love telling that story. lee

Hi Lee! You can't possibly know I'm old too. But that made your Pythagorean Theorem story all the more pleasurable. I taught physics for 45 years and in that time Pythagoras and his insight into right triangles came in more handy than one would think in a world dominated by things very, very small and very, very large. I hope you gave yourself a heartfelt pat on the back for such a clever solution to the garage door caper. As for receiving a garage door opener from your wife for Christmas, it is my opinion that there is nothing that says "I love you" more than receiving such a gift. You are a very, VERY lucky man. Continued good fortune with Time Machine. Kind regards, Luigi

MODERATORS! HELP! Something is wrong with this discussion regarding how comments are presented. They are NOT in chronological order but rather in some random way and it is incredibly difficult to find responses to posts. ALSO, comments are disappearing. I posted a comment yesterday, Jan. 31, asking if MacOS 15.3 had fixed the problem. That comment is now gone. dbrewood posted on Feb. 1 a series of steps he had performed and the result was that his TM backups were working for 5 straight days. That comment is also gone. I have searched every page of this discussion for the above two comments and can't find them. I wonder how many other comments have disappeared. BTW, if I missed the above comments and they are actually somewhere in this discussion, I apologize. But if I am correct, would you kindly check out this issue and see if it is rectifiable? In advance, than you for your assistance. Mr. Luigi

i can't find mr luigi's post to respond to so i'm posting here. this is really in agreement with

"MODERATORS! HELP! Something is wrong with this discussion regarding how comments are presented. They are NOT in chronological order but rather in some random way and it is incredibly difficult to find responses to posts. ALSO, comments are disappearing. I posted a comment yesterday, Jan. 31, asking if MacOS 15.3 had fixed the problem. That comment is now gone. dbrewood posted on Feb. 1 a series of steps he had performed and the result was that his TM backups were working for 5 straight days. That comment is also gone. I have searched every page of this discussion for the above two comments and can't find them. I wonder how many other comments have disappeared. BTW, if I missed the above comments and they are actually somewhere in this discussion, I apologize. But if I am correct, would you kindly check out this issue and see if it is rectifiable? In advance, than you for your assistance. Mr. Luigi"

i agree. i can't find anything. a scatter post algorithm is not helpful. plus, mr luigi is correct that posts disappear.

Underneath the pinned post there's a link where you can sort by rank or oldest. Default is rank. You can save your preferred sort order in your account's preferences.

If you are responding to a post it helps to use the quotes in the edit bar at the bottom of the text entry box. This makes it clear which post you're responding to.

If posts are disappearing then it's because the Mods deleted them for no following the rules.

Well I’m very sad to share that the TM backup problem has returned once more. This is with a freshly rebuilt Mac and newly formatted backup drive.

I’ll be responding to my Apple Support ticket advising their ‘solution’ didn’t work.

At least it saves me from wiping my wife’s iMac which suffers the same issue.

I've been trying to work out commonalities between my old Mac build, the new build and the apps my wife uses. Alas logic does not allow any apps which may be common across all machines.

I still think it's a macOS issue.