Unity does not start in Ubuntu 13.04
Solution 1:
The old methods of replacing unity no longer work in 13.04. Please try:
dconf reset -f /org/compiz/
unity --reset-icons &disown
Reboot if it doesn't work right away.
Solution 2:
I had the same problem, but when I tried
unity --reset-icons &disown
I got the message unity was not properly installed. Never did I uninstall it, but reïnstalling using
sudo apt-get install unity fixed this problem for me.
PS: Use Ctrl+Alt+T to open a terminal