Time Machine backup disk ejected during sleep

Earlier today a Time Machine backup was running on my MacBook Pro, which was plugged in and unattended. I forgot to activate Amphetamine, like I usually do, and came back to find the Time Machine hard drive disconnected and a Disk Not Ejected Properly message. The external drive reappeared within a few seconds of my Mac waking up. I am surprised that the drive got disconnected, especially so as the Mac was connected to the power adapter. I expect the OS to eject external drives before going to sleep.

I am concerned about the integrity of my Time Machine backup and of any damage the drive might have suffered. I was wondering what I should do to ensure that everything is in working order. I reckon that out of extreme precaution I could reformat the drive and run the fsck commands sudo fsck_hfs -fS and/or sudo fsck_hfs -fy -S (my knowledge with this is very limited!) to rule out any damage to the drive and start afresh with a new backup if all is well. Would this be overkill? Would love to hear suggestions from the community.

I’ve had this happen with external SSDs. If you reboot, plug back in the external drive, and tell Time Machine to start a backup (in the Menubar Time Machine menu), and it starts and finishes without errors, then you’re good to go.

Pretty drastic to reformat the drive and start over, of course.


I’ll second @anon41602260‘s advice, and also add that I think it’s extremely unlikely that the disk itself would have suffered any damage.


Why bother to have your Mac sleep when plugged in? Just have the display shutoff and let stuff run. Only let it sleep when in battery.

Thanks guys. I have reconsidered my rather drastic plan after hearing from you! I plugged the drive back in and it did a scheduled backup without any hitches. Hopefully it is fine.

You might want to try recovering a file or two from various backups.


Good deal. Hope this continues to work out for you.

Yesterday, as it happened, I ejected a Samsung 1TB T5 that I used for Time Machine. I ejected it using Finder, and checked with Time Machine to be doubly sure that it was not running. Pulled the USB connector from the laptop, and macOS complained I had inappropriately removed a drive. Today, plugged the drive back in and Time Machine did its thing without error. The T5 is fine. So, sometimes macOS gives off false warnings.

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