Error CS1703: Multiple assemblies with equivalent identity have been imported - Xamarin + VSTS
<p>I upgraded to the latest Xamarin for Visual Studio 2015 (Community Edition), recompiled my projects, checked in a few small code changes and my VSTS build server fails with this error message:</p>

<blockquote>
  <p>[error]CSC(0,0): Error CS1703: Multiple assemblies with equivalent
  identity have been imported: 'C:\Program Files (x86)\Reference
  Assemblies\Microsoft\Framework\MonoAndroid\v1.0\mscorlib.dll' and
  'C:\Windows\Microsoft.NET\Framework\v4.0.30319\mscorlib.dll'. Remove
  one of the duplicate references.</p>
</blockquote>

<p>Internet searches return nearly no details about this issue in general and no valuable information at all in the context of VSTS and Xamarin.</p>

<p>The only code change that I consider to be relevant to the issue was done by Visual Studio in the project file:</p>

<p><a href="https://i.stack.imgur.com/eIwbP.png" rel="noreferrer"><img src="https://i.stack.imgur.com/eIwbP.png" alt="enter image description here"></a></p>

<p>I only develop for Android, am on Xamarin 4.2 and use the JDK 8 u101.</p>

<p>Any idea how to solve this issue?</p>