I have the same problem with Ubuntu 13.04. If you look into the .xsession-errors(.old) file it will tell you: ==========================================
PolicyKit daemon disconnected from the bus. We are no longer a registered authentication agent. ** Message: Got disconnected from the system message bus.... (deja-dup-monitor:2793): GVFS-RemoteVolumeMonitor-WARNING **: Owner of the volume monitor org.gtk.Private.UDisks2VolumeMonitor disconnected from the bus; removing drives/volumes/mounts (update-notifier:2716): GVFS-RemoteVolumeMonitor-WARNING **: Owner of the volume monitor org.gtk.Private.UDisks2VolumeMonitor disconnected from the bus; removing drives/volumes/mounts (nautilus:2393): GVFS-RemoteVolumeMonitor-WARNING **: Owner of the volume monitor org.gtk.Private.UDisks2VolumeMonitor disconnected from the bus; removing drives/volumes/mounts (gnome-setting-daemon:3421): libupower-glib-WARNING **: Couldn't connect to system bus: Failed to connect to socket /var/run/dbus/system_bus_socket: File or directory not found -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1157780 Title: "stop networking" crashes window manager To manage notifications about this bug go to: https://bugs.launchpad.net/unity/+bug/1157780/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
