failed to load session ubuntu

Weil ich auch das schon hatte, folgende Anleitung:

Repair attempt.
Please open tty (virtual console, text mode only): ctrl+alt+f1
Enter:
sudo apt-get update
sudo apt-get install ubuntu-desktop
sudo apt-get -f install
sudo dpkg-reconfigure ubuntu-desktop
sudo reboot
If above wasn’t sufficient try:
sudo apt-get install gnome-session
sudo apt-get install lightdm
sudo apt-get install unity-greeter
sudo dpkg-reconfigure lightdm


Von: http://riveridea.wordpress.com/2012/03/22/how-to-solve-failed-to-load-session-ubuntu/

Oder auch:

A little digging on the internet and the solution which worked for me was to install unity-2d:

sudo apt-get install unity-2d

Then i just restarted GDM:

sudo restart gdm