title: Missing System.Windows
body: <p>I have a rather large solution with some Silverlight and WPF projects inside it, as well as some class libraries and other things.</p>
  
  <p>One of the project is a class library that references a SilverLight application which references <code>System.Windows</code></p>
  
  <p>But at runtime, I get the error:</p>
  
  <p><code>{"Could not load file or assembly 'System.Windows, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e' or one of its dependencies. The system cannot find the file specified.":"System.Windows, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e"}</code></p>
  
  <p>I looked in the GAC (<code>C:\Windows\assembly</code>) and couldnt see it in there...</p>
  
  <p>Whats happening here? </p>
  
  <p>The reference is to: <code>c:\Program Files\Reference Assemblies\Microsoft\Framework\Silverlight\v4.0\System.Windows.dll</code> which DOES exist.</p>