During the installation process, in the Database Information window the error below is displayed:
Desktop Authority requires an instance of Microsoft SQL Server to store its configuration and reporting data.
Database connection error
Cannot connect to the database instance Server_Name\MSSQLServer
Instance names cannot contain the terms Default, MSSQLServer, or other reserved keywords. If a reserved keyword is used in an instance name, an error will occur.
Run the SQLExpress installation file and create a new named Instance with the name DESKTOPAUTHORITY, then point the installation to this instance: Server_name\DESKTOPAUTHORITY
To see more details about the instance names, please visit this Microsoft site