Can't Connect To Localhost On SQL Server Express 2012 / 2016
Answer : According to Aaron Bertand: You need to verify that the SQL Server service is running. You can do this by going to Start > Control Panel > Administrative Tools > Services , and checking that the service SQL Server ( SQLEXPRESS ) is running. If not, start it. While you're in the services applet, also make sure that the service SQL Browser is started. If not, start it. You need to make sure that SQL Server is allowed to use TCP/IP or named pipes. You can turn these on by opening the SQL Server Configuration Manager in Start > Programs > Microsoft SQL Server 2012 > Configuration Tools (or SQL Server Configuration Manager ), and make sure that TCP/IP and Named Pipes are enabled. If you don't find the SQL Server Configuration Manager in the Start Menu you can launch the MMC snap-in manually. Check SQL Server Configuration Manager for the path to the snap-in according to your version. Verify your SQL Server connection authentication mode matche...