After intstalling 13.04 as a fresh install on a blanked hard disc about a week ago all was well until today.
Now my menu bar that appears above the open desktop has vansished! The launcher is still present, as are the menu bars in any applications I have open.
I hvae installed the compiz configuration manager and the unity plugin seems to be enabled.
I've also installed the unity tweak tool, but no amount of messing around with that will bring the menu back.
I've tried logging in as a guest user and the problem is still there.