title: Could not load file or assembly 'System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies
body: <p>I have this exception generated on some user machines (~1 of 20):</p>
  <blockquote>
  <p>Could not load file or assembly 'System, Version=4.0.0.0,
  Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its
  dependencies. The system cannot find the file specified.</p>
  </blockquote>
  <p>I found several references to this error over the web and this site but nothing helped.</p>
  <p>I have an add-in application which uses WCF to connect to the server. The add-in built with .NET Framework 3.5 with VS 2008.</p>
  <p>The error is reproducible on one of the test machines in only one user account. I install my application and can only reproduce this from one account on this machine everywhere else it is working fine. Furthermore it is only reproducible with only one version of host application which I created add-in for (I assume because it uses differnet .NET Frameworks).</p>
  <p>I have checked the fuse logs and I see the following:</p>
  <hr />
  <pre><code>Assembly manager loaded from:  C:\Windows\Microsoft.NET\Framework64\v2.0.50727\mscorwks.dll
  Running under executable  C:\Program Files\SolidWorks Corp\SolidWorks\sldworks.exe
  --- A detailed error log follows. 
  
  === Pre-bind state information ===
  LOG: User = Home\User
  LOG: DisplayName = System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
   (Fully-specified)
  LOG: Appbase = file:///C:/Program Files/SolidWorks Corp/SolidWorks/
  LOG: Initial PrivatePath = NULL
  LOG: Dynamic Base = NULL
  LOG: Cache Base = NULL
  LOG: AppName = NULL
  Calling assembly : System.Configuration, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a.
  </code></pre>
  <hr />
  <p>So by some reasons it is trying to use <code>v2.0.50727\mscorwks.dll</code> loader to load the <code>Version=4.0.0.0</code> of <code>System.dll</code>. On build machine I'm referring 2.0.0.0 version of <code>System.dll</code>.</p>