title: Installation Failed: Invalid Argument -iOS Extension
body: <p><a href="https://imgur.com/vFn0S7g" rel="nofollow noreferrer">https://imgur.com/vFn0S7g</a></p>
  <p>I am about to build watch app target from existing project. I encountered a strange error upon finishing build that unables me to run the watch app properly. Here is the attached screenshot.</p>
  <p>Environment</p>
  <ul>
  <li>OSX 10.10</li>
  <li>XCode 6.2 Beta</li>
  <li>Simulator iPhone 6 iOS 8.2</li>
  </ul>
  <p>When I try creating new watch app project and try the Lister demo app they work just fine. So I am suspecting there is something wrong with my existing project but not sure what since the error message is not really explanatory. I appreciate any leads or helps given, thank you for your time.</p>
  <p><strong>EDIT</strong>: After few investigation turns out <strong>extensions</strong> do not work as well.</p>