Some M1 Macs Affected By Fast User Switching Screensaver Bug
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!)
Popular Stories
Apple today announced that its next-generation CarPlay experience, now dubbed "CarPlay Ultra" begins rolling out today, starting with Aston Martin vehicles.
Subscribe to the MacRumors YouTube channel for more videos.
CarPlay Ultra is now available with new Aston Martin vehicle orders in the U.S. and Canada. It will also be available for existing models that feature the brand's next-generation ...
Apple's recently announced CarPlay Ultra promises a deeply integrated in-car experience, but not all iPhone users will be able to take advantage of the new feature.
According to Apple's press release, CarPlay Ultra requires an iPhone 12 or later running iOS 18.5 or later. This means if you're using an iPhone 11, iPhone XR, or any older model, you'll need to upgrade your device to access...
Apple today released iOS 18.5 and iPadOS 18.5, the fifth updates to the iOS 18 and iPadOS 18 operating systems that came out last September. iOS 18.5 and iPadOS 18.5 come a little over a month after Apple released iOS 18.4 and iPadOS 18.4.
The new software can be downloaded on eligible iPhones and iPads over-the-air by going to Settings > General > Software Update. The iOS 18.5 update has a...
President Donald Trump has asked Apple CEO Tim Cook to halt the company's manufacturing expansion in India, in a potential disruption of Apple's plan to shift iPhone production away from China.
"I had a little problem with Tim Cook yesterday," Trump said during his state visit to Qatar, according to Bloomberg. "He is building all over India."
"They [India] have offered us a deal where...
Apple today announced the launch of CarPlay Ultra, the long-awaited next-generation version of its CarPlay software system for vehicles.
CarPlay Ultra features deep integration with a vehicle's instrument cluster and systems, built-in Radio and Climate apps, customizable widgets, and more. The interface is tailored to each vehicle model and automaker's identity, and drivers can also adjust...
Apple this week introduced a new feature designed to allow prospective Apple Music users to import their saved music and playlists from third-party music services to Apple Music.
The feature is either in an expanded testing phase or it has started rolling out, and it is available in Australia and New Zealand according to an Apple Support document. Signs of the transfer option first surfaced...
The first videos of Apple's CarPlay Ultra experience are now available, providing a never-before-seen look at the long-anticipated iPhone-linked infotainment software.
British automaker Aston Martin today shared the first video of Apple's CarPlay Ultra experience in-action, followed by a detailed walk-through of the CarPlay Ultra system on Top Gear's YouTube channel, which provides the...