I'd like to share a 3 hours hint success here, because I used the keywords "ubuntu logout bug" and went through here during my search.
But my answer was here: ".Xauthority sometimes owned by root, which blocks login" https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/871667/comments/30 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/951404 Title: Ubuntu 12.04 session don't open with lightdm To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/951404/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
