title: Simulator error FBSSystemServiceDomain code 4
body: <p>I'm trying to run an app in the simulator but get this error message:</p>
  
  <pre><code>Unable to run app in Simulator
  An error was encountered while running (Domain = FBSSystemServiceDomain, Code = 4)
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/U5pHD.png" alt="Screenshot for error"></p>
  
  <p>I've not seen any previous references to this from googling around.</p>
  
  <p>Its using XCode 6 Beta, the app is in Swift which links to a Obj-C static library. It runs fine on the device.</p>
  
  <p>Any ideas?</p>