Found the culprit. ~/.config/monitors.xml Somehow corrupted, XML format was ok, contents were not. Attached the file, suffix "yikes".
** Attachment added: "~/.config/monitors.xml that corrupts screen when no external monitor" https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1081922/+attachment/3441735/+files/monitors.xml.yikes -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xserver-xorg-video-intel in Ubuntu. https://bugs.launchpad.net/bugs/1081922 Title: Screen resolution bonkers on undock To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1081922/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp