The app does not use storyboard, actual code in product: (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { UIWindow *window = [[UIWindow alloc] initWithFrame: [[UIScreen mainScreen] bounds]]; mainMenuViewController = [[MainMenuViewController alloc] init]; navigationController = [[UINavigationController alloc] initWithRootViewController: mainMenuViewController]; window.rootViewController = navigationController; self.window = window; [self.window makeKeyAndVisible]; return YES; }

Resolved. In the app, all UI elements was created manually and all ViewController inherited from a BaseViewController, including MainMenuViewController. a. the code caused the issue: @interface BaseViewController: AVPlayerViewController b. modified code: @interface BaseViewController: UIViewController Why the base ViewController inherited from AVPlayerViewController, because there's a VideoViewController that will be used to play video. unfortunately, OC don't support multiple inheritance, so I have to embed the base ViewController's functions into VideoViewController instead of inheritance. It's an issue caused by not being careful enough when modifying code.