Xcode版本6.1.1，新建一个IOS -》Application -》Single View Application，除了AppDelegate文件之外，还有系统自动建立的ViewController，之后我修改了ViewController的名字，运行时报错Unknown class ViewController in Interface Builder file

解决办法：

reddit找到：

        It seems like you have set a custom class named "Descript" for your viewcontroller in the storyboard by accident. Select the viewcontroller in the storyboard and go to Identity Inspector and check whats set as custom class there.

        这里我打开Main.storyboard文件，选中Home View Controller，在右侧的Identity Inspector中的custom class项上，修改Class为我改名后的文件就OK了（其实这里只要修改为一个存在的ViewController即可）。