Disallow multiple KDE logins per user to prevent profile corruption

This is an odd one. SDDMs multi user support is still quite buggy. The worst part is, that it often leads to a user logging in a second time without realizing it, starting a second parallel KDE session which is not handled well and can lead to a whole bunch of annyoing issues.

Strangely this is easily preventable by setting this flag:
in /etc/sddm.conf


This will prevent a second session being created, unfortunately this still can leave a user in a situation where he seemingly can not log in (gehts thrown back to SDDM login screen) unless he knows to use ctrl + alt + FX switching… But for me this is still a big improvement to before.


This may not be helpful to you, but I thought I’d comment. I recently decided to throw out sddm and lightdm on a new installation and only start by command line invocation of wayland plasma startup. It may be by chance (and it is a new clean installation), but boy, my session seems much swifter and more stable without those session managers running.