What you need to know Many M1 Mac users are reporting issues with Fast User Switching which leaves them unable to dismiss their screensaver. The only apparent fix so far is to disable the feature. A new M1 Mac bug is leaving many users unable to dismiss their screensavers when trying to use Fast User Switching. As reported by MacRumors: 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. 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.