The "Xlib: extension "GLX" missing on display ":0"" message suggests it's indeed a problem with the GPU. I found that it could be caused by bugs with nvidia drivers. This could be the case, as mine it's an optimus laptop with NVIDIA GTX 850m.
-- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1543458 Title: Xorg crash prevents login To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers-352/+bug/1543458/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : [email protected] Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp

