Bug in macOS Fast User Switching logs out M1 Mac users

Posted:
in General Discussion edited March 9
An unknown number of Apple Silicon users who have two or more accounts on their M1 Mac are seeing their screensaver spontaneously start and them being logged out.

Apple Silicon
Apple Silicon


Apple's Fast User Switching -- introduced in 2003's OS X Panther, and a convenient security feature -- is reportedly causing problems with some M1 Macs. The feature lets users have more than one login account on their Mac, including a Guest one, and switch between them. However, that switching feature is reportedly activating unexpectedly.

What happens is that a user can be working at their Mac when, without prompting, it displays a screensaver -- and logs the user out. More, it's not possible to clear the screensaver unless you:

  • Close and reopen the lid on MacBook Air or MacBook Pro

  • Tap the Touch ID or Power buttons, or

  • Press Alt-Command-Q to call up the login screen



  • Any of these will allow a user to log back in and continue working, but none of them prevent it happening again. According to MacRumors, which first spotted the issue, disabling the screensaver makes no difference.

    The problem has been reported on all three of the currently-shipping M1 Macs. It also appears to persist through each version of macOS Big Sur that is running on them.

    Apple has not commented.

Comments

  • Reply 1 of 7
    There are a number of issues with fast use of switching. Even on the Catalina there were problems using the touch ID button to switch between accounts. And a big Sur, there are further issues with the touch ID button system not working at all. Fast use of switching using Touch ID Used to work a treat, but now it’s well and truly broken. Interesting to see that It is even more broken and the M1. It used to be a fabulous system, but now the coders in that department are clearly asleep.

    Maybe they’re having a slumber party with the people who code Apple dictate who are responsible for the errors in this message.


    asdasd
  • Reply 2 of 7
    Rayz2016Rayz2016 Posts: 6,957member
    The problem is that hardly anyone uses it, so the few that do use it get a bad experience because Apple doesn’t pay any attention to it. 
    watto_cobra
  • Reply 3 of 7
    auxioauxio Posts: 2,328member
    It used to be a fabulous system, but now the coders in that department are clearly asleep.
    Sounds like they're missing some regression tests in that area.  Automation catches these things far better than people can.
    watto_cobradewme
  • Reply 4 of 7
    Glad I am waiting till the March MacBook Pros coming out.  Was very tempted at buying the M1 Air.  Maybe I will wait till the MacBook Air design gets updated since I like the idea of fanless notebook maybe in 2022?
    edited January 18
  • Reply 5 of 7
    Someone on a different site said that setting up a hot corner of the screen for sleeping the system is one workaround. If the glitch happens, just move the cursor to the designated corner and the system will sleep and waking will get you back to the desktop.
    watto_cobra
  • Reply 6 of 7
    This article, like the one on MacRumors, is way behind, and quite inaccurate.

    The problem is with Big Sur (and possibly earlier OSes), not the M1 macs. It can occur on Intel too. It's possible that it's more common on M1s because 3rd-party software is a little more unstable on M1s. (This would have to do with CrashReporter coming up more often; see the comments on MacRumors for details.)

    This bug is also reported as fixed in 11.2 beta, though I can't confirm that as I'm not running it.
    watto_cobradewme
  • Reply 7 of 7
    asdasdasdasd Posts: 5,668member
    auxio said:
    It used to be a fabulous system, but now the coders in that department are clearly asleep.
    Sounds like they're missing some regression tests in that area.  Automation catches these things far better than people can.
    This feature is particularly hard to test automatically though. The first account is switched out. The next account is switched in.  Anything running in the first account is suspended ( I suppose) and communication isn't easy. Its the kind of thing they do need to add to a test suite though. I never use fast user switching even though I have an account for the wife on my personal MacBook Pro, and she uses it. She just logs me out and her in, and vice versa. 
    watto_cobra
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