MVC 6: System.IO.FileNotFoundException: Could not load file or assembly 'System.Diagnostics.DiagnosticSource
<p>I got this error in my staging environment but don't get it in my local environment. The staging server is Windows Server 2008 R2.</p>

<pre><code>System.IO.FileNotFoundException: Could not load file or assembly 'System.Diagnostics.DiagnosticSource, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.
</code></pre>

<p>The staging environment was working at one point and this error is recent. I get this error from the error log. The site just spins and does not display anything.</p>

<p>Both environments have the same dnx version</p>

<pre><code>C:\Users\Me&gt;dnx --version
Microsoft .NET Execution environment
Version:      1.0.0-rc1-16609
Type:         Clr
Architecture: x86
OS Name:      Windows
OS Version:   6.1
Runtime Id:   win7-x86
</code></pre>

<p>The solution is using dnx-clr-win-x86.1.0.0-rc1-update2.</p>

<p>I added the package 'System.Diagnostics.DiagnosticSource' to all projects in the solution and deployed it. That did nothing.</p>

<p>I grabbed the System.Diagnostics.DiagnosticSource.dll from the packages directory and dropped it into 'runtimes\dnx-clr-win-x86.1.0.0-rc1-update2\bin' directory. I then get an error this error</p>

<pre><code>Could not load file or assembly 'System.Numerics.Vectors, Version=4.1.1.0
</code></pre>

<p>I placed the System.Numerics.Vectors.dll into the bin directory like I did with the DiagnosticSource.dll but I still get the missing Vectors.dll error. I don't believe I should be placing DLLs into the runtime bin directory. How do I solve this?</p>

<p>Update </p>

<pre><code>Active Version           Runtime Architecture OperatingSystem Alias
------ -------           ------- ------------ --------------- -----
   1.0.0-beta8       clr     x86          win
   1.0.0-beta8       coreclr x86          win
   1.0.0-rc1-final   clr     x64          win
   1.0.0-rc1-final   clr     x86          win
   1.0.0-rc1-final   coreclr x64          win
   1.0.0-rc1-final   coreclr x86          win
   1.0.0-rc1-update1 clr     x64          win
   1.0.0-rc1-update1 clr     x86          win
   1.0.0-rc1-update1 coreclr x64          win
   1.0.0-rc1-update1 coreclr x86          win
  *1.0.0-rc1-update2 clr     x86          win             default
</code></pre>