At a client I tried to install SharePoint 2010. It could not find my named instance of the database.
When I enabled Named Pipes, it worked however.
How to enable Named Pipes:
– go to your database server
– go to the SQL Server Configuration Manager
– Go to SQL Server Network Configuration – Protocols for YourNamedInstance
– on the right hand side of the screen you can double click on Named Pipes and enable them
Marijn Somers (MVP) has over 14 years experience in the SharePoint world, starting out with SP2007. Over the years the focus has grown to Office 365, with a focus on collaboration and document management. He is a business consultant at Balestra and Principal Content Provider for "Mijn 365 Coach" that offers dutch employee video training. His main work tracks are around user adoption, training and coaching and governance. He is also not afraid to dig deeper in the technicalities with PowerShell, adaptive cards or custom formatting in lists and libraries. You can listen to him on the biweekly "Office 365 Distilled" podcast.
check de Windows Firewall on the SQL Server