I've been developing apps for the iPhone for a little while. Just recently I got an idea for a mac app. I started Xcode, chose cocoa application written in objective c, and it gave me a starting template like usual. However right away there was build errors, "UIKit/UIKit.h" not found. Xcode has no problem finding UIKit when I write apps for the iPhone. Also, none of my classes even use UIKit, so why does it matter if it can't find it?