Custom view has this code and if I remove @IBDesignable error disappears. @IBDesignable class cCustomView: UIView {     @IBInspectable var demoString: String?;     override func prepareForInterfaceBuilder() {         super.prepareForInterfaceBuilder();     } } Screen shot with error: Apple engineers, how can I fix this error and get Interface Builder to work? I don’t think you released a non-working product.

Wait few days and search crash reports at: Xcode Menu -> Window -> Organizer -> [Select Your App] -> Reports If empty then maybe application uses more memory than the system can allocate and iOS terminate application. In this case, no crash report is sent.

Write Xcode version and wait for someone to confirm that this version works with the Apple Connect (no certificate issue). And you need to use the current version of Xcode.