I updated a machine to Kubuntu 18.04 by a complete reinstall. We still have user management using NFS/NIS. Packages are installed, users can log in. I have one local user dhlocal (userid: 1000) with home directory /localhome/dhlocal and users like dh (userid: 5000) with home dir /home/dh.
I can log in dhlocal to the X/KDE session and work there without any problems - if only that user is logged in.
The session is not registered:  "PID 11214 does not belong to any known session"
XIO:  fatal IO error 4 (Unterbrechung während des Betriebssystemaufrufs) on X server ":0"
XIO:  fatal IO error 2 (Datei oder Verzeichnis nicht gefunden) on X  server ":0"
after 3523 requests (3523 known processed) with 0 events remaining.
XIO:  fatal IO error 2 (Datei oder Verzeichnis nicht gefunden) on X server ":0"
after 1122 requests (1122 known processed) with 0 events remaining.
QProcess: Destroyed while process ("kwin_x11") is still running.
Unexpected response from KInit (response = 0).
startkde: Could not start ksmserver. Check your installation.
. Logging in has this 20+ seconds delay which happens even before any bash startup file in $HOME or /etc is executed. I do not know where this comes from.
What's going on here? How can I fix this? Is any further information needed?
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