Version: (using Devel) OS: Linux Installed from: Compiled sources KDE Shutdown hangs after playing the KDE-Systemsound. There is no "Freeze", you can work as if nothing had happened. BUT there is no reaction, if you try to Shutdown again. A work around is, to disable KDEs Systemsound to play the "Shutdown-Melody".
this problem occurs when another process is using sound system. I thing that kde sound system try to lock soundcard exclusively which is wrong feature (via alsa?). Is also wrong that dead[Z] knotify4 blocks logout/reboot/halt. A have not installed jack or other soundserver. I had same problem - i had to disable kde sound system
Please reopen if this is happening with KDE 5.