title: WatchKit: unable to find interface controller class
body: <p>I tried adding an interface controller to a storyboard, setting its Custom Class to a WKInterfaceController subclass, launched the app in the simulator and navigated to the specified interface controller.</p>
  
  <p>When I do so, I get the following error:</p>
  
  <blockquote>
    <p>WatchKit error - unable to find interface controller class 'TestController' to instantiate</p>
  </blockquote>
  
  <p>If I try to interact with the controller (e.g. try launching its button's action), I get the following error:</p>
  
  <blockquote>
    <ul>
    <li>*********** ERROR -[SPRemoteInterface _interfaceControllerClientIDForControllerID:] clientIdentifier for interfaceControllerID:(null) not found  </li>
    <li>*********** ERROR -[SPRemoteInterface _interfaceControllerClientIDForControllerID:] clientIdentifier for interfaceControllerID:7120004 not found</li>
    </ul>
  </blockquote>
  
  <p>I tried <a href="https://stackoverflow.com/a/28364797/35690">setting the module name as recommended on this answer</a>, but that still gives me the following errors:</p>
  
  <blockquote>
    <ul>
    <li>WatchKit error - unable to find interface controller class '_TtC29myWatchApp_WatchKit_App19TestController' to instantiate  </li>
    <li>*********** ERROR -[SPRemoteInterface _interfaceControllerClientIDForControllerID:] clientIdentifier for interfaceControllerID:(null) not found</li>
    <li>*********** ERROR -[SPRemoteInterface _interfaceControllerClientIDForControllerID:] clientIdentifier for interfaceControllerID:6E20004 not found</li>
    </ul>
  </blockquote>