title: Failed conversion from .net core 2.2 to 3.0
body: <p>Last week I upgraded my .NET Core Web API from 2.2 to 3.0.</p>
  
  <p>I had a lot of issues with packages and still struggling.</p>
  
  <p><strong><em>Case 1:</em></strong> What I have right now is that all of my tests are failing:
  unit tests, integrations tests, etc.</p>
  
  <p>I'm using:</p>
  
  <ul>
  <li>Nunit  (3.12.0)</li>
  <li>NUnit3TestAdapter (3.15.1)</li>
  <li>Moq 4.13.0</li>
  <li>Microsoft.NET.Test.sdk (16.2.0)</li>
  <li>Microsoft.AspNetCore.Mvc.Testing</li>
  </ul>
  
  <p>When I start debugging my tests I get the following error message:</p>
  
  <blockquote>
    <p>System.IO.FileNotFoundException HResult=0x80070002
      Message=Could not load file or assembly 'Microsoft.IntelliTrace.Core, Culture=neutral, PublicKeyToken=null'. The system cannot find the file specified.
      Source=System.Private.CoreLib.</p>
  </blockquote>
  
  <p>The error occurred in the <code>RuntimeAssembly</code> file (part of system.private.corelib), method <code>InternalLoadAssemblyName</code>.</p>
  
  <p>When I continue I get this: </p>
  
  <blockquote>
    <p>System.Reflection.ReflectionTypeLoadException: 'Unable to load one or more of the requested types.
    Could not load file or assembly 'Microsoft.IntelliTrace.Core, Version=16.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.'</p>
  </blockquote>
  
  <p><strong><em>Case 2:</em></strong> When I'm not debugging my tests but just run my application en startup swagger, I can use every call but my output window is filled with thousands of Exceptions like thrown:</p>
  
  <blockquote>
    <p>'System.InvalidCastException' in Swashbuckle.AspNetCore.SwaggerGen.dll</p>
  </blockquote>
  
  <p>This happens when the Linq class <code>Where.SpeedOpt.cs</code> is used and the <code>List.cs</code> class of generic, also in <code>System.Private.CoreLib</code>.</p>
  
  <p>Are case 1 and case 2 related to each other?</p>
  
  <p>Anyone have a workaround or solution?</p>