“Application windows are expected to have a root view controller at the end of application launch” error only on iPad
Change the following line: [_window addSubview:[_navigationController view]]; to: _window.rootViewController = _navigationController; or, if you need iOS 3 compatibility: if ([_window respondsToSelector:@selector(setRootViewController:)]) { _window.rootViewController = _navigationController; } else { [_window addSubview:_navigationController.view]; }