Why would my MacBook Pro 14' with M1 chip be sending me 98 warnings overnight that an external disk used for time machine backup would not be ejected properly. Then after I eject the drive but don't pull the plug, it reconnects and in the time I finish writing this note, gives six more "Disk Not Ejected Properly" warnings.
MacBook Pro 14″, macOS 13.1
This almost certainly is some kind of hardware incompatibility. I would focus on the cable, adaptor, hub etc. being used to connect to the drive, everything in between the drive and the Mac needs to be checked. I think the least likely problem is with the Mac USB-C port, unless it was somehow damaged physically in some sort of mishap. More likely is a cable, adaptor, or the external drive itself. But you should start by trying with a new cable, checking that the connections are secure and solid, and using a direct connection if possible.
Is this new behavior? If so, what changed?
Does the drive work stay mounted properly on another Mac?
Does this happen in Safe Mode?
What type of external drive? Has it been working properly in the past?
Some external drives will eject like that when the Mac goes to sleep. I have Western Digital, Samsung, G-Drive, etc. external drives that work properly with a sleeping Mac, but we also use Apricorn Fortress drives (with a touchpad for unlocking) that always eject when the Mac sleeps. You can try changing the sleep settings so that the Mac itself never sleeps but the display is allowed to sleep, go blank, or revert to a screensaver.
"Disk Not Ejected Properly"
