Black screen after switching user

Hi all

My desktop PC is used by the family and each member has an account.
Hence, it is required to log off and the log in each time another user wants to use the computer.

The thing is that after multiple logoff / login (not the same number each time but usually 2 or 3), the user login will end up with a black screen after successfully have passed the SDDM identification step.

I don’t know how to troubleshoot that. I have not found straightforward tips on the system log.
The only thing that I have noticed is, despite a user is logged off, there are still processes (like kwin_w11) running for this old user despite another user has logged in.

Do you have any idea how to solve that ?


I read more and more on this topic and I saw black screen issue often points to X11.
However, I have not found a solution. I have not found or understood which log and information to search for…
Could anyone at least give me some hints for the troubleshooting ?

Thanks again.

Hi again

I just found this post and I am trying the fix proposed.
Sometimes to time, we don’t see what is just below our nose. :roll_eyes:

I will report whether it solves my issue; hopefully, it does! :slightly_smiling_face:

Well, just tried after modifying /etc/systemd/logind.conf as explained but it doesn’t change anything.
I still have my black screen issue and when I don’t, I still have the other processes running. It looks like setting KillUserProcesses=yes doesn’t work for me.

Any idea ?


Hi again

Following @Aragorn advise, I removed systemd from group and passwd in /etc/nsswitch.conf
Not any better, saddly. :sob:

What does work is :
and login again in SDDM

My wife will not do that…

Is there anything to learn from that ?


You need to reboot after changing that setting, else it will not be applied by the system manager…

Those are separate issues IIRC…

Thanks @TriMoon for your support :+1:

Yes indeed, I have done a reboot but it doesn’t help.

It is actually what I wonder. I am stating that because when I log out (after ctrl-alt-del), then alt-F2 and alt-F1, log in again, I don’t have anymore the other users’ processes running and all work fine.

Any idea how to keep troubleshooting ?


Maybe this is a bug of KDE. From:

This has been fixed with Plasma 5.20.3:

But Manjaro currently has KDE Plasma 5.20.2 on stable.
So wait a little until 5.20.3 hits stable and see if it fixes the problem.

Thanks @Bleuzen

I guess Plasma 5.20.3 is not so far way for the stable branch.
I will wait a bit then.

After last stable update, Plasma 5.20.3 seems to do the trick!

Thanks all.

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