title: What do these Mono/xbuild warnings mean and how do I fix them?
body: <p>I build VS2010 projects with Mono's xbuild 2.10.5.0. The projects use the '.NET Framework 3.5 Client Profile' as the target framework (they must be 3.5 compatible and I don't need more than the client profile parts).</p>
  
  <p>I'm getting the following warnings:</p>
  
  <pre><code>Build succeeded.
  
  Warnings:
  
  c:\Project\MyProject.csproj (default targets) -&gt; C:\PROGRA~2\Mono\lib\mono\4.0\Microsoft.Common.targets (GetReferenceAssemblyPaths target) -&gt;
      C:\PROGRA~2\Mono\lib\mono\4.0\Microsoft.Common.targets:  warning : Unable to find framework corresponding to the target framework moniker '.NETFramework,Version=v3.5,Profile=Client'. Framework assembly references will be resolved from the GAC, which might not be the intended behavior.
  
  c:\Project\MyProject.csproj (default targets) -&gt; C:\PROGRA~2\Mono\lib\mono\4.0\Microsoft.Common.targets (ResolveAssemblyReferences target) -&gt;
      C:\PROGRA~2\Mono\lib\mono\4.0\Microsoft.Common.targets:  warning : Reference 'mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' not resolved
      C:\PROGRA~2\Mono\lib\mono\4.0\Microsoft.Common.targets:  warning : Found a conflict between : 'System' and 'System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. Using 'System' reference.
      C:\PROGRA~2\Mono\lib\mono\4.0\Microsoft.Common.targets:  warning : Found a conflict between : 'System.Core' and 'System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. Using 'System.Core' reference.
  </code></pre>
  
  <p>I'm afraid I don't understand these and the only Google hit for <a href="https://encrypted.google.com/search?q=%22Unable%20to%20find%20framework%20corresponding%20to%20the%20target%20framework%20moniker%22">"Unable to find framework corresponding to the target framework moniker"</a> is the commit for that error message.</p>
  
  <p>What do these warnings mean and how can I fix them? Is the 'client profile' not supported by Mono at all? If so, I couldn't find anything about that in the Mono documentation. What causes the unresolved <code>mscorlib</code> reference and where are these two <code>System</code> references it reports a conflict between?</p>