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Some M1 Macs Affected By Fast User Switching Screensaver Bug

MacRumors

macrumors bot
Original poster
Apr 12, 2001
51,488
13,129


A growing number of user reports online suggest some of Apple's M1 Mac models are susceptible to a Fast User Switching bug that spontaneously activates the screensaver and leaves the user unable to dismiss it.


In macOS Big Sur, Fast User Switching allows users to quickly switch between user accounts without having to completely log out. Based on posts in the MacRumors forums, Apple Community forums, and on Reddit, however, a screensaver can sometimes take over the screen of Apple Silicon Macs without notice, rendering the desktop workspace completely unavailable.

While the screensaver appears on the screen, the mouse pointer is still on top and moving, but nothing else works, and users have to close and re-open the lid on their MacBook Air or MacBook Pro, or light press the Power/Touch ID key or use the Alt-Command-Q key combination to get back to the login page.
MacRumors forum member drmacnut:

Brand new Mac mini M1, 2nd day using it, Big Sur macOS 11.1 (20C69) with screensaver and screen sleep set to 20 mins. I was actively editing some Calendar entries when all of a sudden the same exact thing happened (screensaver on, user locked out). I ended up using Remote Access from my MBP to get in and log out the user on the Mini. The Mac mini then jumped to the login screen and it's working fine again now. Very weird.
Apple Community forums member Squeaks2369:

I am experiencing the same issue. M1 MacBook Air. Big Sur 11.0.1. Happens on two separate user accounts, both with the screensaver disabled. No way to exit the screensaver but to close then open the lid. Happens a few times a day while actively using the computer. Browsing various forums it appears others are having this issue as well.
Video shared by MacRumors forum member dawideksl

Disabling Fast User Switching prevents the issue from happening, but that obviously leaves the login feature inaccessible. Having the screensaver disabled in System Preferences for all users doesn't seem to make a difference either.

The issue has been reported on M1 MacBook Air, M1 13-inch MacBook Pro, and M1 Mac mini models, and occurs on all versions of macOS Big Sur, including the latest 11.1 update. Affected users are advised to submit feedback to Apple to hopefully facilitate a fix.

(Thanks, Chris!)

Article Link: Some M1 Macs Affected By Fast User Switching Screensaver Bug
 

eddjedi

macrumors 6502a
Sep 7, 2011
520
538
I'm sure they will fix it soon enough, but things like this are why I never jump on major architecture changes immediately. If you depend on your device for work, you need some level of stability. I'm keen to migrate to Apple Silicon, but will probably wait until 'M2'
 
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Alchemist

macrumors regular
Dec 22, 2004
134
65
UK
Yep, we've experienced this also, on our MacBook Air (M1 8/8core, 8GB, 512GB) but I hadn't linked it to fast user switching yet. Frustrating. we have found that closing and reopening the lid is a quick workaround. Hopefully they'll get an update out soon.
 
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skardvin

macrumors newbie
Nov 15, 2015
13
20
No wonder when Craig Federighi opened the M1 MacBook Air to show off the spontaneous wake from sleep that it didn't have this issue...🤔🙄 he must have had to disable fast user switching first before filming. 😂
 
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c.R.o

macrumors newbie
Jan 2, 2021
1
0
Yea I got this problem on my m1 MacBook Pro, I fast switch to another account and it goes into screen saver. I tap the trackpad and nothing happens. Esc or force to quit and nothing.
Sometimes it does it when I open a preference panel and the screen has goes all black too

Only way I could fix this bug was closing the laptop and opening the screen up again.
 
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Serban55

macrumors 6502a
Oct 18, 2020
613
1,063
I'm sure they will fix it soon enough, but things like this are why I never jump on major architecture changes immediately. If you depend on your device for work, you need some level of stability. I'm keen to migrate to Apple Silicon, but will probably wait until 'M2'
Its an soft issue not an m1
We had on the 16” mbp also for some weeks now
So if this is not fixed on software level..you will get this with m2 or m30 as well
 
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Steve121178

macrumors 603
Apr 13, 2010
5,376
4,624
Bedfordshire, UK
Had this issue various times. Seems to be a problem when the Mac is left idle for a long period of time.

Also, Time Machine takes an aaaaaaage to backup. Hopefully just another software issue.
 
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paulvee

macrumors regular
Jun 23, 2003
174
425
NYC
I agree with this. Probably a Big Sur issue. Would be very weird if it was a Hardware bug (though, potentially, moving from the T2 security chip to secure enclave on the M1, _could_ be a factor).
Exactly. I didn’t even have it with fast user switching, but I did have the cursor over screensaver bug on my 16 inch.
 
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miric

macrumors member
Sep 29, 2016
90
41
I've had the same issue on Catalina and MBP 15 2017 recently. Fixed by falling MBP asleep when the screen saver process was closed by OS I suppose.
 
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