sudo apt-get update

sudo apt-get upgrade

sudo apt-get dist-upgrade

sudo apt-get clean

sudo apt-get autoclean

sudo dpkg --configure -a

sudo -f

sudo apt-get install ubuntu-desktop ubuntu-session unity-control-center unity-settings-daemon xul-ext-webaccounts

sudo apt-get install --reinstall ubuntu-desktop

sudo apt-get install gnome-shell ubuntu-gnome-desktop

sudo apt-get install gnome-shell

sudo apt-get install ubuntu-session

sudo dpkg-reconfigure -a

sudo aptitude install <packagename>

sudo apt-get install --fix-broken

sudo apt-get autoclean

sudo apt-get autoremove

sudo apt-get -f install

sudo rm .Xauthority .

Changing .Xauthority ownership didn't work

chown username:username .Xauthority

Changing the user directory rights didn't work

sudo chmod -R u+w /home/[username]

I tried meddling with lightdm

dpkg-reconfigure lightdm

sudo mv ~/.Xauthority ~/.Xauthority.backup

sudo service lightdm restart