Instance Name

QBM uses a default instance name, which is called SQLExpress, to connect to SQL Server. However you can change this instance name if you already have a different instance name.  To change the instance name use File->Data Utilities->Settings

If the SQL Express is not started automatically, you must restart your computer in order for the SQL Express to be started or you can start the service by going to Windows services and find the instance name that QBM is using and start that service.