Ubuntu 16.04 不会关机。当我转到屏幕右上角的图标并单击关机时，它不会关机。我跑了shutdown -h now，这就是我得到的：
tanner@tanner-x151x:~$ shutdown -h now
Failed to set wall message, ignoring: Interactive authentication required.
Failed to power off system via logind: Interactive authentication required.
Failed to start poweroff target: Interactive authentication required.
See system logs and 'systemctl status poweroff.target' for details.
Failed to open /dev/initctl: Permission denied
Failed to talk to init daemon.
tanner@tanner-x151x:~$ sudo shutdown -h now
[sudo] password for tanner:
Failed to start poweroff target: Transaction is destructive.
5ee system logs and …