title: Could not load file or assembly 'AjaxControlToolkit' after upgrade to .net 4.0
body: <p>I have a web application that I am attempting to upgrade to .net 4.0.</p>
  
  <p>I took the application and opened it via Visual Studio 2010 Beta 2 and selected the upgrade path for that application.  The application uses the AjaxControlToolkit.  Now that the upgrade is complete when I attempt to access a page I get the error message: "Could not load file or assembly 'AjaxControlToolkit' or one of its dependencies.  Access is denied."</p>
  
  <p>I've tried:</p>
  
  <ul>
  <li>Restarting my machine</li>
  <li>Clean Solution</li>
  <li>Removing all files in Temporary ASP.Net Files</li>
  <li>Relaxing permsissions (added Everyone with Full Control) on the Bin directory, the Temporary ASP.Net Files directory</li>
  <li>Removing and readding the reference to the AjaxControlToolkit DLL</li>
  </ul>
  
  <p>The related web.config entries for the AjackControlToolkit are:</p>
  
  <pre><code>&lt;pages controlRenderingCompatibilityVersion="3.5" clientIDMode="AutoID"&gt;
    &lt;controls&gt;
      &lt;add tagPrefix="ajaxToolkit" namespace="AjaxControlToolkit" assembly="AjaxControlToolkit"/&gt;
    &lt;/controls&gt;
  &lt;/pages&gt;
  </code></pre>
  
  <p>Any ideas as to what is occuring here/how I can fix this issue?</p>