(In reply to Dirk S. from comment #5) > Looks like kwin failed to start/crashed. > /usr/bin/kwin_x11 is running > Did you reboot after the last update? > yes > Does it work on a fresh user account? > yes Ok, so it's not a general problem. > What happens if you run kwin_x11 in konsole inside the running user session? > I.e. what output do you get? > kwin: unable to claim manager selection, another wm running? (try using > --replace) That means that kwin was already running... Did you try that on the new account? I actually wanted to see the output from the session where it was failing to start. > What displaymanager are you using? > I have no changed anything. I don't know. So let's assume it's sddm. I only asked because I noticed a problem with kdm in Plasma 5.19.5 (a fix for that is pending). But then kwin should still start anyway... > I've rename the home directory and created a new one. Now it is working > again. Any idea what files should I compare to find out what happened? ~/.config/kwinrc would be the first thing I'd imagine. Could you please try to move everything back except this one please?