title: Why does the Android emulator report "unknown virtual device", when the device is in my user directory?
body: <p>I installed all the <a href="http://developer.android.com/sdk/requirements.html" rel="noreferrer">prerequisites for Android development</a>. I created a virtual device through Eclipse and tried to run the Hello World sample application in that device. I received the following error message.</p>
  
  <blockquote>
    <p>emulator: ERROR: unknown virtual device name: 'Android21Device'<br>
    emulator: could not find virtual device named 'Android21Device'</p>
  </blockquote>
  
  <p>I get the same error when I try to start the device from the command line and through the SDK program.</p>
  
  <p>I can see the device directory and files at </p>
  
  <blockquote>
    <p><code>D:\Users\anthony\.android\avd\Android21Device.avd</code></p>
  </blockquote>