I recently upgraded to 13.04 and since then my desktop, seemingly randomly, logs me off and goes back to the login screen.
This goes very fast. There is no message or warning, no freeze (or it should be for a tiny fraction of a second).
After logging in all programs are closed.
It seems random. Sometimes after 5 minutes with only firefox running. Sometimes after hours with plenty of programs running. Sometimes after being away and simply moving the mouse.
I problably could do a clean install, but I would rather know what is happening and how I can fix this, but I have no idea where to begin to debug this.
Anybody any ideas how I could find the cause?