Thank you, I had it in view and that was creating another instance(s). With single instance of WatchMotionManager, it now stops the motion updates. struct MotionDataView: View {     @ObservedObject var stopWatchManager = StopWatchManager()          var body: some View {         VStack{             Button(action: {                 if labelText == "Start" {                     self.stopWatchManager.start()                 }                 else if labelText == "Stop" {                     self.stopWatchManager.stop()                 }