title: The default XML namespace of the project must be the MSBuild XML namespace
body: <p>I cloned the <a href="https://github.com/aspnet/SignalR" rel="noreferrer">ASP.NET Core SignalR Repo</a> locally, and try opening the solution from within the following environment.</p>
  
  <p><strong>IDE</strong></p>
  
  <pre><code>Microsoft Visual Studio Enterprise 2015
  Version 14.0.25431.01 Update 3
  Microsoft .NET Framework
  Version 4.6.01055
  </code></pre>
  
  <p><strong>DOT NET CLI</strong></p>
  
  <pre><code>λ dotnet --info
  .NET Command Line Tools (1.0.0-preview2-1-003177)
  
  Product Information:
   Version:            1.0.0-preview2-1-003177
   Commit SHA-1 hash:  a2df9c2576
  
  Runtime Environment:
   OS Name:     Windows
   OS Version:  6.1.7601
   OS Platform: Windows
   RID:         win7-x64
  </code></pre>
  
  <p>I end up seeing a lot of these kinds of error messages:</p>
  
  <blockquote>
    <p><code>..\Repos\SignalR\src\Microsoft.AspNetCore.SignalR\Microsoft.AspNetCore.SignalR.csproj</code>
    : error  : The default XML namespace of the project must be the
    MSBuild XML namespace. If the project is authored in the MSBuild 2003
    format, please add
    <code>xmlns="http://schemas.microsoft.com/developer/msbuild/2003"</code> to the
     element. If the project has been authored in the old 1.0 or
    1.2 format, please convert it to MSBuild 2003 format.  <code>..\Repos\SignalR\src\Microsoft.AspNetCore.SignalR\Microsoft.AspNetCore.SignalR.csproj</code></p>
  </blockquote>
  
  <p>I want to know how to fix this the correct way.</p>