Had same issues as described above (update manager - no privilege, shutdown/restart not working out of menu) after upgrade from 14.04 to 14.10.
Following fixed everything: sudo apt-get install systemd-sysv -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gdm in Ubuntu. https://bugs.launchpad.net/bugs/1240336 Title: Not authorized to perform operation / Unable to determine the session we are in: No session for pid To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gdm/+bug/1240336/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs