Availability.h, UIKit.h, etc not found

Question

I\'m having a great problem here.

I recently downloaded Xcode 4.3 from the Mac App Store, because it had the full-screen feature for Lion. And then, my project stopp

Answer 1

To try reinstall your XCode. I lost a lot of time when look for the problem. Then I tried reinstall my XCode because I could not see header files in each frameworks. And that helped me.