title: SQL Schema Comparison Error "Target is unavailable"
body: <p>When comparing an SQLServer project in Visual Studio 2015 Update 2 against a database SQL Server 2012, it shows the error "Target is unavailable" or "Source is unavailable" when change the direction.</p>
  
  <p>It used to work properly a couple of months ago. Is there any workaround? I couldn't find any.</p>