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Ubuntu 20.04 Issues

For some reason it can happen that for a particular user on a particular machine lightdm (login manager) decides to load the gnome session (albeit it should load xfce per default). It does so despite no full gnome desktop environment is installed. It seems that somehow the d-bus is wrongly configured (?) or started (?), not sure. Anyway, the effect is that even logout or restart does not fix this. The user is greeted with a pretty blank gnome desktop environment running on top of xfce (the later is therefore inaccessible).

This seems to fix this: sudo dbus-send --system --type=method_call --print-reply --dest=org.freedesktop.Accounts /org/freedesktop/Accounts/User<UID> org.freedesktop.Accounts.User.SetXSession string:xfce make sure to replace <UID> with the affected users id.

Issuses during update to 16.04

Especially in the course of the update of 14.04 to 16.04 the following issues have turned out to happen quite often. The text was copied from Ingo's mail to the admin list.

• the .dmrc problem: if something else than "plasma" is specified in

this file in the home directory of the user, you'll get a "can not load session" (or similar) error message. Since lightdm sort of "caches" the value of this file in a file of its own, this can be very annoying to sort out.

• the .Xauthority problem: can happen if a machine is newly installed

and the user has worked on that machine before the update, i.e. a wrong key is stored in .Xauthority

• akonadi / baloo crap: if enabled, these daemons cause heavy IO load

and potentially slow down / inhibit login or make the machine barely usable while creating the databases

• useless KDE animations: on older or weaker machines, enabling (or not

disabling) tons of KDE animations can make the machine very slow, or might even crash the graphics driver

• reboot necessary: as it turned out in Marias case, the machine needed

a reboot. It seems that the new KDE is new more touchy w.r.t. a necessary reboot. I.e. if KDE components have been updated by the nightly cron jobs, the KDE/Ubuntu 16 system services (dbus et al)

apparantly do not get along very well any more causing these frozen logins and a reboot is needed. ==> if this happens more often, we have to think about whether we can continue with the nightly updates, or whether we do them only once a week and have reboots afterwards (something like "reboot Monday" or similar).

• possibly some other cron job may interfere with the new KDE causing

these frozen logins.