M1 MacBook Pro "Disk Not Ejected Properly" several times during sleep

I was having the same issues on an M1 MacMini with a OWC ThunderBay Flex 8. I followed what others have said in this thread and still the drives would just unexpectedly disconnect/disk not eject properly. I did the following ' I set the slider for "Turn Off Display" to never and checked "Prevent computer from sleeping automatically when the display is off". ' and so far after 48 hours I have not had a single drive report "unexpectedly disconnect/disk not eject properly".

I am not sure if this will work for everybody but so far it has worked for me.

I have a new M1 Mac Mini and have been experiencing "Disk Not Ejected Properly" issues with a variety of external disks. In my case, they are not restricted to the sleep/wake events discussed by others on this thread, often unmounting whilst active.

I have done extensive cross-testing of multiple drives and cables with the M1 Mac Mini and a 2016 Macbook Pro, at first running MacOS 11.2 and then retesting with the 11.3 update. The disks seem to be stable when connected to the USB-A ports directly or via USB-A/USB-C connections made via an Anker 10-port USB Hub when its connected to the Mac Mini via USB-A.

Connecting the drives directly to the USB-C ports on the Mac Mini results in either disconnection when sleeping, or in the case of a brand new Lacie 10TB D2 Professional drive (firmware updated), also during activity. The latter will not infact stay connected and cannot be repaired or erased when it is mounted. It's signature blue light flashes rapidly whatever its state of activity.

At this point in time, it would seem to me that the problem is a compatbility issue between the new USB 4 ports and legacy USB 3.1 drives (and potentially other USB peripherals).

I am at a loss to know whether this issue can be solved by a software update, but as of the newly released MacOS 11.3 it persists.

I solved that same issue by unchecking the "Put disks to sleep whenever possible" checkbox in the Battery setting in the tab of "Battery" and also in "Power Adapter".

MacBook Air (M1, 2020)

My MacOS is Big Sur 11.1

PS: I've only tried this with a power adapter connected and did not had any more problems, I don't know if I'll have an issue without it. For now all good, I'll keep you posted!

Good luck, hope that helps...

I think I cracked the problem - in Big Sur - there is no energy saving tab , but there is a battery option in the system preferences & change the "turn display off after "from the 1 minute or so default to say 1 hour . Its not disconnected for the last half hour at least. Will update if it stays that way

Same problem on my M1 Mac Mini, but only since I upgraded to 11.2.1 last night - and after a long phone session with Customer Support (despite their best suggestions and a complete reinstall of the system software) the problem remains.

So...

New (about 2 month old) Mini with and external 1TB SSD with 2 partitions plugged into a Thunderbolt port. 1 partition, containing my various documents, photos, etc. always mounted and visible on the desktop. The other, empty in anticipation of eventually having a bootable clone drive, always unmounted.

Until last night, there were only 2 occasions when I got the "Disk Not Ejected Properly" notice, and on both those occasions the monitor hadn't woken from sleep either, so I assumed the problems were related. (Also, possibly related, about one time in 10 or 20, when I choose Sleep from the Apple menu, it immediately wakes back up, and I have to put it to sleep a second time. This hasn't changed after the update.)

So anyway, after the update last night, EVERY time I put the mini to sleep it dumps the external drive, but here's the interesting thing. With only one of the partitions mounted before sleep, when I get and close the 'not ejected properly' notice on waking, but do NOTHING to remount the partition, after about a minute, the Mini goes out and remounts both partitions by itself. I found this interesting, so then tried unmounting both partitions of the 1TB drive (but kept it connected), but plugging in an external 256GB into another slot, and leaving it mounted while I put the computer to sleep. On waking, I get the notice about the 256GB drive, do nothing, and the Mini tracks down and mounts BOTH external drives (both partitions of the 1TB and the 256 GB).

So it somehow appears that if the external drive wasn't deliberately ejected before sleep, the computer 'knows(?)' something went wrong, and goes out polling its ports for connected drives. Perhaps that might provide a clue as to what's going on.

Additionally, during the time with Customer Service, it was suggested to me a couple of times that a recommended preventative was to connect the drive to external power. I explained that these external drives A) are solid state, so don't need to be keeping disks spinning during sleep, and B) don't have anywhere to plug external power into anyway. Plus, given that the only variable between the computer working till last night and not working now, is the new system update - so there has to be something in the software causing this.

I'm also wondering if there's something in the code to dump external drives during sleep to preserve the batteries of laptops, but it's not taking into account that that's not necessary for a plugged-in desktop unit.

Anyway, open for suggestions - and if there's a specific place where it would be useful to submit these details to Apple for their bug solvers to peruse, let me know and I'll send it in there too.

Thanks,

Check the options under ”power adapter”?

In any event, the “put hard disk to sleep when possible” option didn’t resolve the issue for me.

What resolved it for me, was making the Thunderbolt SSD my startup disk. Perhaps this keeps it sufficiently active to prevent a timeout of some kind that’s occurring when it’s used as a secondary disk.

In my system, the performance of the external (boot) SSD matches the performance of the internal SSD within 5%, so I don’t mind booting from it.

Mac mini M1 2020 / MacOS Big Sur 11.2 beta / VisionTek 1TB Thunderbolt 3 Portable External SSD

Update on my previous reply to someone on this thread:

I can confirm that this likely MacOS bug resolved for me, after I started using the external TB3 SSD as a boot drive.

As a non-boot drive, I got uncommanded disk ejection about every 20 seconds. Using it as boot drive, I’ve had zero ejections in 2 months.

My theory is that using it for boot, keeps something from timing out. Perhaps swap or some other process keeps the SSD sufficiently active.

It's not a fix. It's a workaround for anyone (like me) who needs to use their external TB3 SSD while waiting for a fix.

It's also the results of an experiment, which a) tends to rule out compatibility issues as the root cause, and b) supports the theory that this is an OS bug.

I am still seeing an occasional disconnect, but it isn't frequent. I have "Put hard disk to sleep when possible" checked and "Prevent computer from sleeping automatically when the display is off" unchecked. Both drives are connected via a USB-C "UGreen" hub.

Having same issue with MacBook Air M1 using macOS Big Sur 11.2.3. I have two external SSD drives, so far only the SanDisk Extreme Pro 1TB (newest model) portable is getting disconnected during sleep mode. This doesn't happen ever when laptop is being used. This drive is only used for Time Machine backups and I am concerned that it may end up getting corrupted. I have switch the two external drives so that the Sandisk is now plugged directly into the one available TB port I have left and the other external SSD is now plugged into the CalDigit dock. I will update if this makes a difference but I am doubtful that it will.

This is happening to me with the same hardware, Mac OS Big Sur 11.1, with external USB SSD drives connected to a CalDigit Thunderbolt 3 dock. The exact same configuration did NOT result in improper ejects when connected to a MacBook Pro 15" 2018 also running Big Sur 11.1!

Many thanks for the quick reply . just bought it should receive it . Where is the put disks to sleep whenever possible option ? will try that too. While I bought the cal digit for convenience & expansion, But why do we have to buy an external piece of hardware to make the laptop work as it should . Apple should really look at this - this is a flagship model

Thanks! Under "power adapter" it's not there either but if it didn't help for you, I'll try the other.

To make this happen, can you tell me where to go to switch it? making the Thunderbolt SSD my startup disk