I've had persistent problems with a 5 minute hang at shutdown for the last three versions of Kubuntu (13.04, 13.10, and now 14.04). I suspect this is not a KDE-specific problem. Recently, I performed a fresh installation of Kubuntu 14.04 from a live-USB, and shutdown worked normally for about a week. The hang-up is now happening again, and I can't figure out why.
In Gentoo, How do I allow normal users to shutdown/reboot?
I try to shutdown as my user el but get this response:
el@voyager ~ $ shutdown now
shutdown: you must be root to do that!
Usage: shutdown [-akrhPHfFnc] [-t sec] time [warning message]
-a: use /etc/shutdown.allow
-k: don't really shutdown, only warn.
-r: reboot after shutdown.
With 11.2 and Gnome occasionally it will not shutdown properly. I press the shutdown button and then Gnome starts the shutdown sequence. It terminates the desktop and falls back to GDM, which in it self is normal. However it then just stops, I can't click anything and the system is not responding either. When I press the physical button on my PC I get the menu of shutdown again.