do you use usb-c enclosure?
does it disconnect when touching/moving usb-c connector?
from my experience, usb-c is not reliable and will get loose after some usage, either cable or port inside the mac
Yes it is a usb enclosure: usb-b jack (the bigger shape that generally "hangs on" better than tiny rectangle or rounded rectangle end). Have tried 3 usb-c to usb-b and 3 usb-a to usb-b cables testing
EVERY port on Studio Ultra as well as 3 external hubs (2 powered and 1 using bus power) as “middlemen.”
Same cable linked to prior iMac running macOS
before Big Sur was stable for about
2 years: no “unexpected ejections.” Cable runs are relatively far from where any hands work on keyboard or mouse- no cable jiggles whatsoever.
Unhook
same cable from Studio Ultra or Hub and plug into 2 older Macs or a PC and all is fine. Use the
same cable to try
different enclosures and some work fine, including another from the
same (Mac reliable) brand. Thus, it very likely can’t be the cable, connection, enclosure, drive, age, etc.
This story implies sleep causes it and there may be a partial catalyst in sleep… but I get “unexpected ejections” while actively using Studio and drive, such as currently read/writing from/to it… so obviously neither end is asleep. This important enclosure acts as a giant scratch disc for video editing. I've since subbed in another without as much storage space because I need the reliable connection. But I'd like the BIG one to be back in play for that kind of work.
My best gut guess is that there is power sipping algorithms good for iDevices in desktop Mac code that need not worry about battery. The code eases the power down, down, down to minimize power draw (to maximize a battery that doesn’t exist) until
some enclosures lose the “I'm still here” connection to Mac. Sleep gets the blame but I suspect that it’s the TIME that passes that leads to these disconnects, not really because of sleep. For example, my problematic enclosure can go through a bunch of manual sleep-wake cycles in a few minutes and never disconnect. However, leave it connected for up to about 3 hours and somewhere during that timetable (and it does seem quite random), it will very likely "unexpectedly disconnect" whether the Mac sleeps or not.
All of my older Macs slept on the exact same schedule as my Silicon Mac and did not have this problem. But Intel Macs took no PPW-focused, battery management code from iDevices in
their creation. This is just a deductive guess of course. Only Apple would actually know.
And again, this is not one users problem. Many people post about this in many threads here and around the internet, including Apples own support forums. A variety of enclosures were stable pre-Big Sur. Install Big Sur or newer and previously-stable drives have “unexpected ejections.” For some, it's important enough to turn around and downgrade back to BEFORE Big Sur and the drive is stable again (all other variables are the same). That seems to SHOUT where the problem lies.
Not all enclosures do this, just some… like it’s MSB instead of USB, the M meaning MAYBE. In my own testing, I dug out long-since retired enclosures from all the way back into the 2000s to try a wide variety of drives. Some of those oldies were stable vs. this relatively new enclosure "unexpected ejections." And again, the substitute I've slugged in while waiting on Apple to get around to hopefully fixing the bugs is from the SAME brand and has been perfectly stable for a year now. Unfortunately, it can't offer as much storage capacity.
At least THIS story says Apple dug into SOME code in the ballpark of this problem. Maybe the BUG implied to be tied to sleep and SATA is actually the bug affecting Macs other than only Mac Pro in this way? Hopefully some NOT Mac Pro people chime in saying this upgrade fixed their "unexpected ejection" problems (too). I haven't got to try it myself yet.