title: Problems with references to TPL Dataflow and TPL in VS 2012 RC
body: <p>I just upgraded Visual Studio 11 Beta to the new Visual Studio 2012 RC and have problems referencing TPL Dataflow.</p>
  
  <p>First, I tried to reference Dataflow as I did previously, by adding a reference from the framework. But when I try to do that, I get an error box:</p>
  
  <blockquote>
    <p>A reference to 'System.Threading.Tasks.Dataflow' could not be added.</p>
  </blockquote>
  
  <p>and then the whole Visual Studio freezes.</p>
  
  <p>After reading <a href="http://blogs.msdn.com/b/bclteam/archive/2012/05/30/mef-and-tpl-dataflow-nuget-packages-for-net-framework-4-5-rc.aspx">MEF and TPL Dataflow NuGet Packages for .NET Framework 4.5 RC</a>, I assumed the version of Dataflow that showed in the references list was some kind of artifact of the previous installation. So, I tried using Dataflow from NuGet, which seemed to work, until I actually tried to compile my code, because I got an error:</p>
  
  <blockquote>
    <p>The type 'System.Threading.Tasks.Task' 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'.</p>
  </blockquote>
  
  <p>This is confusing, because <code>Task</code> is in mscorlib, no other references should be necessary. But there is a reference assembly called <code>System.Threading.Tasks</code> in the references list, so I tried to add that. Unfortunately, a familiar error showed:</p>
  
  <blockquote>
    <p>A reference to 'System.Threading.Tasks' could not be added.</p>
  </blockquote>
  
  <p>and then Visual Studio froze again.</p>
  
  <p>Am I doing something wrong? How can I use TPL Dataflow with VS 2012 RC?</p>