My use case is simply and I wanted the external camera or no camera. I should get back to it soon. To answer your issue the line of code that is added is AVCaptureDevice.self.addObserver(self, forKeyPath: "systemPreferredCamera", options: [.new], context: &systemPreferredCameraContext) You need to add the following property to your class var systemPreferredCameraContext: AVCaptureDevice? = AVCaptureDevice.systemPreferredCamera Hope that is what you are asking about.