When Shutting down or hibernating it just goes to the login screen [duplicate]

Solution 1:

Used to have the same problem, run this on a terminal:

sudo poweroff

The problem get fixed by itself after several times i had to do that.

Also check if theres a .Xauthority file in your home folder owned by root.
Log in a text console (Alt+Ctrl+F1) at the login screen, and then run

sudo rm ~/.Xauthority

Hope it helps. (:

This is a known problem. Here is the associated bug report:

https://bugs.launchpad.net/ubuntu/+source/gnome-session/+bug/838792