If I login on my Ubuntu PC and logout immediately, the system sometimes hangs.
The background screen and icons are displayed and I can even use the mouse to activate the icons and launch programs, but the logout does not proceed - the system appears to be stuck.
There is one workaround: If I hit CTRL-ALT-DELETE, I'm asked if I want to logout and told that the system will log me out in 60 seconds.
This workaround is fine from me, but the freeze is somewhat confusing for my users. Does anyone know what causes this and how to avoid it? My guess is some kind of timing issue with Unity, but that is only a guess. Any suggestions are appreciated.