I think this bug is related to Bug #807306 or even a duplicate. The workaround mv /run/udev /run/udev.old (as root) is also working here. I will mark udev as also affected, but I'm unsure about the duplicate.
** Also affects: xorg-server Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/808654 Title: Failed to load session 'ubuntu' To manage notifications about this bug go to: https://bugs.launchpad.net/udev/+bug/808654/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs