title: Mixed mode assembly is built against version ‘v2.0.50727′ of the runtime
body: <p>I'm getting the following exception:</p>
  
  <blockquote>
    <p>Mixed mode assembly is built against version ‘v2.0.50727′ of the runtime and cannot be loaded in the 4.0 runtime without additional configuration information.</p>
  </blockquote>
  
  <p>as I was trying to export crystal report from my WPF program... </p>
  
  <p>I have added the following in the app.config already...</p>
  
  <pre><code>&lt;startup useLegacyV2RuntimeActivationPolicy="true"&gt;
    &lt;supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/&gt;
  &lt;/startup&gt;
  &lt;runtime&gt;
    &lt;NetFx40_LegacySecurityPolicy enabled="true"/&gt;
  &lt;/runtime&gt;
  </code></pre>
  
  <p>Any experts can help????</p>
  
  <p>Reference I found: 
  <a href="http://www.davidmoore.info/2010/12/17/running-net-2-runtime-applications-under-the-net-4-runtime" rel="noreferrer">http://www.davidmoore.info/2010/12/17/running-net-2-runtime-applications-under-the-net-4-runtime</a></p>