Halp? When I try to launch the app store in Mavericks, it takes about 5 min to open. The first 2 min it's simply unresponsive (no window), and the next couple minutes, it's got a window open but beachballed. When the beachballing ends, clicking any button on the toolbar does nothing, and opening menus on the menu bar results in more beachballing. I've tried repairing permissions and removing the app store preferences plist, the application updates plist (from Application Support), and the app store and storeagent caches... to no avail. Any ideas short of reinstalling OS X?