为什么只看XCode 5中的故事板就会毁了我的应用?

I have an app built in XCode 4 against iOS6. If I open that workspace in XCode 5, clean and build my project, and run it in the simulator, it works (looks a bit different and needs some work, but it works). If I the simply navigate to my Storyboard and I have an app built in XCode 4 against iOS6. If