title: Unit Test Sessions failed to execute
body: <p>I'm using VS2015 professional with resharper ultimate and I've started to get the following error in the unit test session window when I'm executing my unit tests.</p>
  
  <blockquote>
    <p>2016.09.21 14:16:54.745   ERROR System.AggregateException: One or more errors occurred. ---> System.Threading.Tasks.TaskCanceledException: A task was canceled.
       --- End of inner exception stack trace ---
       at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
       at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
       at JetBrains.ReSharper.UnitTestFramework.Launch.Stages.DiscoveryStage.Run(CancellationToken token)
       at JetBrains.ReSharper.UnitTestFramework.Launch.UnitTestLaunch.RunStage(Object stageObject)
    ---> (Inner Exception #0) System.Threading.Tasks.TaskCanceledException: A task was canceled.&lt;---</p>
  </blockquote>
  
  <p>tests of other projects works perfectly in VS2013 but not in VS2015.
  Yesterday I've installed couple of packages on my pc:
  vs14-kb3165756.exe and OpenCover.UI.vsix</p>
  
  <p>I've tried to uninstall the OpenCover package which didn't solved the issue.</p>