time machine disk not ejected properly

I have been following several threads about Time Machine problems in Monterey. After considering and trying a multitude of suggestions, it appears that at least one option has not been mentioned (or at least not found by me). I have a 2020 iMac 27" Intel computer running the latest macOS, namely, the latest update of Monterey, and I use a newly purchased replacement external 8T Mercury Elite Pro HDD as my TM drive. (Its predecessor drive had the same problem before it failed.) Every few days, the HDD used for Time Machine disconnects spontaneously, followed by a message that the 'disk was not ejected properly'. Usually this happens well after a backup completes and the TM continues to churn away for a long time (as indicated by a blinking activity light on the HDD) with what I assume is some post-backup operation. By the time the drive disconnects, the case is VERY hot. Not enough to cook eggs, but hot. Could it be that the post-backup churning that Time Machine imposes on the drive makes the HDD get so hot that it shuts down from heat overload? Even if it does, however, I think this is a macOS issue as indicated by many comments about this shutdown problem on other threads. Does anyone out there have any useful comments that can help me -- and other Mac users -- finally get past this issue?

iMac 21.5″, macOS 10.13

Posted on Jul 4, 2022 9:13 PM

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relh Author

Level 1

35 points

Posted on Jul 15, 2022 2:44 PM

To all who responded to my original comment: After getting a new 12T G-Drive to use for Time Machine (so far, so good - knock on wood), I erased the Mercury Elite Pro 8T drive I had been using and reformatted it as HFS+. I attempted to run a manual backup of a different data drive (containing roughly 2T of data) onto the 8T drive using SuperDuper! and got another improper ejection failure. The 8T drive -- which was a recent warranty replacement -- was clearly a main source of my problems. I still want to run TM for a few weeks on the new G-Drive to be sure Apple does not bear some responsibility, but at this point it looks like it is all due to OWC's drive. Just not up to the job. Thanks for all advice.

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21 replies

Jul 10, 2022 1:03 PM in response to Barney-15E

The 4 Tb drive is a good size and a decent price. The size of your backup drive doesn't set the size of your backup files. Time Machine will check to see which files have changed and then back them up. It only backs up the files that have changed. A disk drive works better if it has plenty of spare space. When the drive gets closer to full, then it often spends a lot of time moving files around if there are not large enough contiguous blocks of file space open. Personally, I always format my backup drive as exFAT since exFAT is recognized by both Apple and Windows. APFS is likely faster but with a backup drive you are not using it constantly like you would the main drive in the computer. I like the versatility of being able to read files with any type of computer.

Barney-15E

Level 10

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Jul 15, 2022 9:33 PM in response to relh

However, an 8T drive that is over half full with multiple backup snapshots probably has to do a lot of file management because of the changes I do make.

it’s not comparing every previous backup. It only compares to the most recent.

It appears all of the churning was due to the bad drive.

relh Author

Level 1

35 points

Jul 16, 2022 12:05 AM in response to Barney-15E

Agreed, Barney. I made the mistake of thinking that the warranty replacement drive would be good. Made me waste a lot of my time and yours working through the problem. I'm not sure I am going to waste my time dealing with OWC on another replacement but I am pretty sure I won't trust one of their HDD units again.

tbirdvet

Level 6

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Jul 9, 2022 6:54 AM in response to Barney-15E

Barney-15E

Level 10

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Jul 9, 2022 9:50 AM in response to relh

I’ve never experienced any “churning” of my backup drives.

Have you completely erased the drive and started over?

relh Author

Level 1

35 points

Jul 9, 2022 12:44 PM in response to LyleFromVegas

Thanks, Lyle. I am leaning toward a G-Drive with a somewhat larger capacity but Seagate is also a contender.

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time machine disk not ejected properly