xcode won't compile iOS apps, crashes when .xib or .storyboard files are opened

Question

I\'m running the very latest version of xcode (4.2.1). And I\'m signed up to the ios developer program.

When I create a new iOS Application for iPhone or iPad, using

Answer 1

I had this same problem and deleting everything in your "Derived Data" folder fixed my issues. In your case: /Users/mark/Library/Developer/Xcode/DerivedData/EmptyViewTest

Maybe this thread will help: How can I safely delete in my ~/Library/Developer/Xcode/DerivedData directory?