Seems that gnome-screensaver is missing from previous upgrades (12.04/12.10) to 13.04.
As per this article (http://askubuntu.com/questions/292227/ubuntu-13-04 -not-locking-screen) it works if you do this: sudo apt-get install gnome-screensaver Hope this can be addressed by the Ubuntu lords. Thanks! -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1173936 Title: Cannot lock screen after update To manage notifications about this bug go to: https://bugs.launchpad.net/unity/+bug/1173936/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs