title: Tests not running in Test Explorer
body: <p>I am currently working on a solution that has currently 32 Unittests. I have been working with the resharper test runner - which works fine. All tests are running, all tests are showing the right test outcome.</p>
  <p>However, the tests are not running when using the Visual Studio test explorer.</p>
  <p>The Test Explorer is showing all unit tests, but once clicking on &quot;Run All&quot;, all tests are getting greyed out and show no result of the test run:</p>
  <p><img src="https://i.stack.imgur.com/HfTGo.png" alt="enter image description here" /></p>
  <ul>
  <li>All test classes are public</li>
  <li>All test classes are having the <code>[TestClass]</code> attribute declared</li>
  <li>All test methods are using the <code>[TestMethod]</code> attribute</li>
  <li>Both the productivity code and the test projects are targeting .NET 3.5.</li>
  <li>I have already tried to clean build my solution, and / or delete all <code>obj</code>, <code>bin</code>, <code>Debug</code> and <code>Release</code> folders</li>
  </ul>
  <p>I'd appreciate any hints which would explain this behaviour.</p>