During the installation of SELECTserver the option to pick SQL Express is grayed out because there's already a SQL database on the server.
If a full SQL Server is installed the Microsoft Windows installer recognizes this and does not offer to install an additional SQL instance.
Recomendations.1) Have the DBA of the SQL Server create an instance for the SELECTserver and provide a username and password to access it.2) Using the SELECTserver Database Setup Tool, enter the provided username and password to configure the SELECTserver application to communicate with the SQL server.3) Follow the prompts to completed installationSQL Express can be manually installed if desired. It would not interfere with the full SQL Server instance.
SELECTserver TechNotes and FAQs