title: The type "x" is defined in an assembly that is not referenced. VS 2010 C#
body: <p>I am having a problem I just couldn't solve and would like some input.</p>
  
  <p>I am working with multiple class libraries in Visual Studio 2010, .net 4.0 Framework, in C#.  I have a class library project which references the assembly output(.dll file) of another Visual Studio solution.  The reference was added correctly to the class library project (correct path, version, etc.).  All types dependant on the referenced assembly are known by the compiler at design time (no red squiglies).  </p>
  
  <p>However, when I attempt to build the project I get the following error:</p>
  
  <p>The type 'x' is defined in an assembly that is not referenced. You must add a reference to assembly 'MyAssembly, Version=1.0.1.1, Culture=neutral, PublicKeyToken=null'.</p>
  
  <p>Note: type name replaced by x above.</p>
  
  <p>It is as if the reference has not been added, but it has.
  Has anyone else encountered a similar problem and discovered a work around?</p>
  
  <p>Thanks so much,
  Andrew</p>