title: Powershell - Missing System.Collections.Generic in C:\windows\assembly\GAC_MSIL
body: <p>I'm trying to use this code in Powershell:</p>
  
  <pre><code>Add-Type -AssemblyName "System.Collections.Generic"
  </code></pre>
  
  <p>However I get this error:</p>
  
  <pre><code>Add-Type : Cannot add type. One or more required assemblies are missing.
  </code></pre>
  
  <p>I've looked in C:\windows\assembly\GAC_MSIL and can see that there is no folder named System.Collections.Generic.</p>
  
  <p>Do I need to download this library, if so where?</p>