title: Unable to determine simulator device to boot. - Xcode
body: <p>I just downloaded Xcode 6 &amp; played with it a bit.</p>
  
  <p>After switching back to previous version of Xcode and running in simulator, I keep getting this error.</p>
  
  <p><strong>Unable to determine simulator device to boot.</strong></p>
  
  <p>How do we resolve this?</p>
  
  <p>Thanks in advance.</p>