The same happens for my system (Dell M6800 with Nvidia Quadro K3100M).
I found on the web somebody who stated to have the solution.
Solution provided, remove the ~/.config/monitor.xml file.
Tried that but then the light went out completely (no graphics anymore, only a
command line prompt).
Even
Ok, I commented the Start on lines at the top of the
/etc/init/gpu-manager.conf file.
This is what I did:
My Laptop has two video cards a Intel Haswell and a Nvidia Quadro K3100M
The laptop was working with the nouveau drivers on the Intel card and that
worked OK.
I upgraded the Intel drivers
