Failing to connect to MSSQLSERVER

Question

I've installed SQL Server 2012 Express. The problem is that I cannot connect to it through MSQL Server Management Studio.

When installing it, I've used MSSQLSERVER as an instance name. I have SQL 2017 running as SQLEXPRESS.

Checking at the services, I can see that it's running.

And here is the image of management studio.

You can see that I am connected to \SQLEXPRESS and for some reason it keeps failing to connect to \MSSQLSERVER

Answer 1

The name MSSQLSERVER is the default instance rather than the name of a named instance. Unlike a named instance (like the SQLEXPRESS instance), the instance name is not specified to connect to the default instance. One can connect to the default instance using the host name alone (assuming default 1433 port) or host name and port number. For a local connection, . or localhost can be specified.