For me it's eve worse - no Itunes at all!! Mid-2010 MBP, updated to Mavericks yesterday, everything working more or less fine (some slow animations in launchpad, but nothing major) until I tried to open the just updated Itunes and I don't get anything!! no Itunes window, nothing at all - and when I try to quit it, it does not work! I need to force quite manually!!
HELP (rebooting did not help)