title: Can't connect to a SQL Server named instance
body: <p>I run several applications that require SQL Server. I usually use SQL Server Express. After the latest Windows 10 update, my profile became corrupted, so reinstalled windows. I had been wanting to play around with SSRS, so I installed SQL Server 2016 Dev edition. After installing, I tried to connect from SSMS  using <code>hostname\instance</code> and Windows authentication and I got error 87</p>
  
  <blockquote>
    <p>A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 25 - Connection string is not valid) (Microsoft SQL Server, Error: 87)</p>
  </blockquote>
  
  <p>I tried removing the instance name and just connecting using the hostname, and the connection succeeded. With SQL Server Express I always needed the instance name. Why is it no longer necessary?</p>