Comment 51 for bug 1247189

I'm using a freshly installed Ubuntu 14.04 with kernel 3.13.0-24 and 3.13.0-29. As soon as I click on a different user I want to switch to in the gearbox menu I get a black screen and nothing else is happening. I'm still able to SSH to that box and top does not show any process taking 100% CPU. Alt+sysrq+b is able to reboot the system as is sudo shutdown now -h

Tried different versions of the nVidia Driver including 331, 319, 310 and 304. This is an HP zBook with nVidia Quadro K3000M plus an embedded Intel. With Hybrid graphics switched off (nVidia GPU only), this problem occurs. With Hybrid Graphics switched on or auto, (Intel GPU active), the GUI does not even start.