Ubuntu 11.10 logs off when clicking shutdown

Is your account set to autologin and is your home folder encrypted? Had same problem and fixed it by turning 'autologin' for user off. Need to do sudo reboot or shutdown -h now from terminal, then either use GUI via User Account settings and turn off autologin or follow these steps from https://bugs.launchpad.net/ubuntu/+source/gnome-session/+bug/838792 :

raggar (mbaart) wrote on 2011-11-04: #24

I found a possible solution to this bug. It has something to do with the auto login >function in the user management from Unity. When activated it cannot shutdown anymore. >Also disable the auto login is not possible anymore.

What I did: gksudo gedit /etc/lightdm/lightdm.conf

remove the line: autologin-user= YOUR USERNAME

Restart your computer with: sudo shutdown -h now

After that I had a system that worked normally again.

Had the same issue and tracked it down to having another account/profile logged in at the same time.

Logged into Account A Switched to Account B (testing a new user) Forgot about A, User B couldn't shutdown and would drop back to the login screen.

Fix : Logout of Account A, B can now shutdown.