Hmmm, second time in a week my M1 MacBook Pro has frozen and restarted itself while I was writing in Apple Mail. All standard up-to-date release versions of software.

Hmmm you're not alone in this; I wouldn't worry about your new hardware! I run into fairly regular bugginess with Mail, particularly a reluctance to quit when I tell it to do so. It just sits there.

hmm interesting. Run diagnostics. Sent back my MBP due to problem with trackpad

@pimoore Good thought re the OS update. Haven't had any other issues at all.

@martinfeld Good to know. I quickly realised both problems came while using Apple Mail so that seems a likely culprit.

@rom I think it tracks back to Apple Mail. Be interesting if the next OS update changes anything.

my M1 Mac Mini too. For me, I think it's the cables I'm connecting to it to have a dual monitor setup.
Still researching but this seems to a big M1 issue

@tiff Interesting. No cables for me — in fact the battery was near fully charged and it wasn't even plugged in to the power.

strange! It's been buggy for me but hoping it's just Big Sur and not the machine as a whole

Are you by any chance running any plugins? I use the excellent MailTrackerBlocker and as of the last OS update, Mail.app started doing weird things -- slow to start and shutdown, random freezes etc. I turned off the plugin, restarted Mail.app and voila everything was back to normal. I then once again turned on the plugin, did the restart dance and have had no problems in the last week and a half.

@tiff I had this frequent freeze and crash issue on my M1 Air connected to a 24" monitor via HDMI. I switched the output to Display Port and have had zero issues since then. Maybe this is worth a try if your monitor supports Display Port.

this is interesting. Been using Mail.app on MBP as well - pretty much stable even with SpamSieve. Is it only retrieving mail from iCloud? Maybe the Mail server is wonky. :)

@rom Thanks for the thought — mail comes from different servers. I'm not actually trying to troubleshoot, just observing the behaviour. If it starts to happen routinely, then I'll worry. 😀

@pimoore I think that's so. I hope the crash reports I'm dutifully sending off to Apple lead to some change somewhere.