I can't shut down nor reboot without console

Solution 1:

Do you have rabbitmq installed? That is the culprit for me. Here is bug ticket for it: https://bugs.launchpad.net/ubuntu/+source/rabbitmq-server/+bug/670289

Solution 2:

I also had the same problem, but for me it is solved with the following solution. Maybe it will help your system too. https://bugs.launchpad.net/ubuntu/+source/gnome-session/+bug/838792/comments/24

See also the rest of the bugreport at: https://bugs.launchpad.net/ubuntu/+source/gnome-session/+bug/838792

Solution 3:

I had the same problem (also a similiar one when I was using Gentoo) and this worked for me: https://www.grendelman.net/wp/policykit-adventures/. Tested it on 12.04 and the problem is gone. I'd use it as a temporary fix though, 'cause something's telling me it's not really that safe when everyone's allowed to reboot the host without any checks for other running sessions. In my case this bug was only manifesting itself when I had other sessions running on VTs, or when there was someone else logged in via SSH. Anyway, hope this fixes it for you. Enjoy :-)

Solution 4:

Problem

I just experienced the same problem on my Linux Mint 12 (aka Ubuntu-11.10) with Cinnamon desktop. The "restart" GUI button logged me out instead of restarting.

Findings

I found your post but met a different solution that "worked for me". I had the same message in my syslog:

gnome-session[12937]: WARNING: Unable to restart system: Authorization is required

I found out that I had two users logged in on my machine:

$ who
root     tty1         2012-12-28 10:14
evigier  pts/0        2012-12-28 10:14 (:0)

root was logged on my main tty, aka ctrl + alt + F1. I started it yesterday because I needed to do some evil admin tasks I cannot remember of.

Solution

I logged out my root user from tty1, got back to my desktop ctrl + alt + F7, then pressed restart.