title: v11.0\WebApplications\Microsoft.WebApplication.targets was not found when file actually references v10
body: <p>First some background.  At the end of 2012 we migrated our vs2008 solution to vs2010 but we still target .NET 3.5.  (I know nothing but the latest and greatest here!)  </p>
  
  <p>We hadn't had any issues with this setup until a few weeks ago when people started getting these errors:</p>
  
  <pre><code>"foo.csproj" (Rebuild target) (16:5) -&gt;
    C:\...\foo.csproj(142,3): error MSB4019: The imported project "C:\Program Files (x86)\MSBuild\Microsoft\VisualStudio\v11.0\WebApplications\Microsoft.WebApplication.targets" was not found. Confirm that the path in the declaration is correct, and that the file exists on disk.
  </code></pre>
  
  <p>The interesting thing is that if you look at the project file it references v10 which makes sense because we don't use Visual Studio 2012.</p>
  
  <p>This error hit several of us at once and even on older code branches that haven't changed in months.</p>
  
  <p>I suspect some update got pushed onto our machines that confused things but I don't know what to do about it.</p>
  
  <p>The short term solution has been to install VS 2012 and not use it but I'm hoping for something a little cleaner than that.</p>