NuGet Package restore failed: Microsoft.Bcl.Build.Tasks.dll used by another process : <blockquote>
  <p>NuGet Package restore failed for project MyProject.Application: The
  process cannot access the file
  'C:\MySolution\packages\Microsoft.Bcl.Build.1.0.21\build/Microsoft.Bcl.Build.Tasks.dll'
  because it is being used by another process..</p>
</blockquote>

<p>Any idea how to fix this issue? Thanks.</p>
