Just upgraded to Ubuntu 13.10 only to find that Unity won't load (login freezes, after doing ctrl+alt+F1, logging in and then doing startx, I get a blank desktop and the mouse pointer, and nothing else). I can right click, but the only operations that work are "create new file" and "create new folder". For example, "change desktop background" doesn't work. Also, after doing a few right clicks and choosing "change desktop background", I get a warning message box: "compiz closed unexpectedly."

Guest login works fine.

Tried creating a new user, but I experience the same thing with the new user.

Tried removing all configuration files from my home directory... same thing.

Doing dconf reset -f /org/compiz/ gives an error "error spawning command line..."

Doing unity --reset also gives errors.

Tried uninstalling unity (and compiz) and reinstalling, but that doesn't help. Tried reconfiguring lightdm, didn't help.

I don't have any proprietary drivers installed.

Once again, the funny thing is that the guest session works fine.