I did a clean install and had exact same problem on a 2011 iMac 27" and a 2013 13" MacBook Pro The xorg.conf was the problem. Copied to to xorg.conf and restarted. Came up good on both machines.
Follow up: On the laptop I forgot to mention I also had to delete everything in ~/.config after copying xorg.conf file. As soon as I did that the desktop was restored.
So:
cd /etc/X11
sudo cp ./xorg.conf.04172014 ./xorg.conf
sudo reboot
cd ~/.config
rm -Rf *
Desktop will reload and work correctly. I've rebooted a few times and it seems to be working. On the laptop I did have to do the remove of everything in .config twice so there is still something a little messed up there I think.
Last edited: Apr 18, 2014