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 restorting the monitor.xml file could not make it work again.
Will try the trick with the /etc/init/gpu-manager.conf file.
The same happens for my system (Dell M6800 with Nvidia Quadro K3100M). monitor. xml file.
I found on the web somebody who stated to have the solution.
Solution provided, remove the ~/.config/
Tried that but then the light went out completely (no graphics anymore, only a command line prompt).
Even restorting the monitor.xml file could not make it work again.
Will try the trick with the /etc/init/ gpu-manager. conf file.
Kind regadrs,