Big Sur hang and crash at shutdown

Right. I was hoping that the 11.2 upgrade would include a fix to this issue. It did not. Un-mounting my external backup drive prior to shutdown solves the immediate issue, but does not solve the problem. Note that my other external drive, used to store all of my photography, does not need to be un-mounted prior to shutdown. I would guess this has to do with Time Machine. It would be helpful to know if someone uses another backup system has the same problem.

I temporarily solve the issue by STOPPING any ongoing job by TimeMachine before shutting down the computer. It's definetly related to the inability of BigSur to deal with TimeMachine software and whichever external unit (NAS in my case) to cease ongoing jobs properly before shutting down.

If I simply press the hotkeys combo to switch off the computer, it will instead panic and reboot with the error.

And 11.2.1 does not mention a fix for this either.

I wonder why in the friggin **** does Apple add a "REPORT" button on their OSs if they won't simply hear at it!?

I have had this problem since catalina, for more than 15 months now. Both on my MBP and iMac. They are backing up differently, the MBP wirelessly on to the airport time capsule, the iMac to an external USB HDD. ( I have reported every single crash and unsurprisingly nothing’s changed ). Was able at times to shut down correctly by manually stopping an ongoing backup and unmounting the backup drive in terminal using diskutil; but without success if there was no backup to interrupt. Both big sur and catalina behave identically.

Good job apple for creating microsoft catalina and microsoft big sur. They should patent the bug, maybe it will bring in additional money.

I've been having this issue, too.

I have the Promise Pegasus R4i installed and a Pegasus3 R4 hooked up via Thunderbolt. I tried a lot of the suggestions I've seen in the communities about reinstalling drivers and ejecting the external enclosure before shutting down or restarting but still experience the problem of the Mac Pro crashing if I try to restart or shutdown.

The partial solution I've found is to close all application and log all users out and then shutdown or restart from the login screen. Not a 100% successful solution, but far better results than anything else, so far.

Based on other feedback in this forum I did finally have time to format the R4i to APFS (case sensitive), which required a long backup and restore process as it serves as my primary data storage device. The Mac Pro only has the 256GB SSD.

The problem I have now is that my work based OneDrive is unable to use the R4i because it's incompatible with APFS (case sensitive.) I realize that technically isn't Apple's problem, but the R4i is promoted by Apple as a plug and play partner solution. It shouldn't require special formatting to prevent a major system issue with restarting and shutting the computer down.

So I can confirm that reformatting the time machine backup drive from HFS+ to APFS (and losing months worth of backups) fixed the crash on shutdown issue. As a parentheses, I wasted days trying to "convert" the HPFS+ to APFS only to realize that Time Machine can't reuse the old backup files anyway plus, First Aid was showing lots of errors past conversion. Don't repeat my mistake.

Best, back up to a third drive temporarily, then erase the main backup drive as APFS/case sensitive, then activate Time Machine on it and deactivate the third drive. ta-da.

I bought a 2019 MBP last summer and set it up with OWC Thunderbay 6-bay RAID. The computer would often crash without warning. And it would often crash at reboot. Eventually I gave up trying to fix and bought a brand new 12-core Mac Pro. Same setup otherwise. Out of the 40 or so shutdowns or restarts I have probably seen no more than 5 that rebooted without error. 1/4 of the time I see the black screen with white text computer error at startup. The rest of the time I get a panic crash on shutdown. Have tried everything. nothing works. Disconnected the thunderbolt3 pro dock. Disconnected the Raid. Have even tried using just one monitor. (I have 2). The only thing I have not done is put the original RAM back in. But I don't suspect this will fix anything. The problem has been around since Catalina. And on a different computer. Maybe Apple is just trying to trick suckers like me into spending $15000 on their machines, thinking money is the trick!

I don’t have the same setup as most of you, but still have the same issue. I have a 2017 iMac Pro. Every since upgrading to Big Sur my shutdown time takes a lot longer (and I have had it hang and not shutdown), before Big Sur it was about 5 seconds. I have one external drive for Time Machine. What seems to work for me is running Clean My Mac before shutting down. If I do that my computer shuts down just like before, 5 to 6 seconds. It seems a lot of the replies here talk about changing the formatting of the external hard drive, I will have to look into this. What is odd is I have an older MacBook Pro with Big Sur and an external hard drive for Time Machine that doesn’t have this problem, it shuts down just as fast as before and doesn’t hang. It is an Apple mystery.

The issue seems to be Kernel related with how the old driver's were installed vs how that are probably migrated under Big Sur. I resolved my issue by reinstalling the drivers for any external drives and the hang on shutdown issue went away.

I shut down slow no matter what I do but sometimes I prevent the crash IF and only IF I manually STOP any ongoing TimeCapsule operation (copy, delete,...) before shutting down.

I use a Synology NAS and afaik this does not use any special drivers other than the OS itself.... :/

Well just logged in this thread after updating to 11.3 *AND* intentionally shutting down the computer with TimeMachine doing a backup (not halting it manually like I was doing lately)....

...and it shutdown without crashing!!

If I don't come back to this thread it may mean Apple finally fixed it!!

It seems as if Apple will never admit they have a problem. This shut down problem with errors and rebooting has been going on for quite some time. Several of us have determined it had something to do with the external hard drive use for Time Machine. When we parked the backup drive first, the computer shut down properly.

Every time there is a system software update I try to shut down normally and the problem seems to persist. Recently I updated to 11.3 and them to 11.3.1 (today). The problem has gone away. I have shut down without error for 5 straight days now - without parking the external hard drive first. It seems as if this problem finally made it into the batch of fixes this time around.

I must add that as soon as I updated to 11.3 on my 2013 Mac Pro, this problem has ceased to occur. It's been a week or so and no reoccurrence (when it used to happen every day since Catalina).

At least for now, I consider this fixed (i.e., who knows what similar problem the Apple devs will foist on us next).

Roger, dodger, over and under.

I have had the same problem however if I eject the Time Machine, after it takes an inordinate amount of time to wake up, it shuts down fine. The TM seems to hang for too long for the MACOS to be able to shutdown.