title: error CS0012: The type 'TaskAwaiter<>' is defined in an assembly that is not referenced
body: <p>When I try to debug my Windows Phone 8.1 project the Locals window is empty, and Watch shows an error for <code>this</code>:</p>
  
  <pre><code>this    error CS0012: The type 'TaskAwaiter&lt;&gt;' is defined in an assembly that is not referenced. You must add a reference to assembly 'System.Threading.Tasks, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'.  
  </code></pre>
  
  <p>Everything else seems to work just fine, there are no errors/warnings related to this, it happens only while debuging. And also not for all projects.</p>
  
  <p>I've tried a few fixes I found on Stack and MDSN, but:</p>
  
  <ul>
  <li>Adding <code>&lt;CheckForSystemRuntimeDependency&gt;true&lt;/CheckForSystemRuntimeDependency&gt;</code> didn't change anything;</li>
  <li>Debug > Options > General > Use legacy VB and C# something is greyed out.</li>
  </ul>
  
  <p>Is there anything else I can try?</p>