16.04: Graphical login/desktop vanished?

[Josef Wolf]

Hello all,

Today, I left my laptop with a freshly installed 16.04 alone. I was logged in
and the screensaver was active.

A couple of hours later, I deactivated the screen-saver and noticed that all
the window decorations and the system tray vanished. That is (AFAIK) the
window-manager crashed?

The only way to shut down the system was to switch to VT1 via CTRL-ALT-F1 and
use CTRL-ALT-DEL to reboot.

Since then, the graphical login won't start anymore.

Any ideas?

-- 
Josef Wolf
jw at raven.inka.de