Sharepoint hates named instances

Although it doesn’t really mention it at installation time, SharePoint won’t install into an SQL Server instance that isn’t named MSSQLSERVER (or at least it’s really not obvious how to tell it the instance name). This causes problems if you’re using SQL Express on a separate server as by default that will install using the instance name “SQLExpress”.

Although the installer blows up with the error below, it did manage to create the database, but then it can’t seem to connect back to it because it doesn’t realise it got created on an instance that isn’t MSSQLSERVER (I have no idea how it managed to create the schema though).

The solution is either to install SQL Express with the “Default instance” name (which is MSSQLSERVER) or to create another instance called “MSSQLSERVER” or to just use the full version of SQL Server which uses that name by default.

Failed to create the configuration database.

An exception of type Microsoft.SharePoint.SPException was thrown. Additional exception information: Unable to connect to database. Check database connection information and make sure the database server is running.
An exception of type Microsoft.SharePoint.SPException was thrown.  Additional exception information: Unable to connect to database.  Check database connection information and make sure the database server is running.
Microsoft.SharePoint.SPException: Unable to connect to database.  Check database connection information and make sure the database server is running. ---> System.Runtime.InteropServices.COMException (0x81020024): Unable to connect to database.  Check database connection information and make sure the database server is running.
  at Microsoft.SharePoint.Library.SPRequestInternalClass.CreateSite(Guid gApplicationId, String bstrUrl, Int32 lZone, Guid gSiteId, Guid gDatabaseId, String bstrDatabaseServer, String bstrDatabaseName, String bstrDatabaseUsername, String bstrDatabasePassword, String bstrTitle, String bstrDescription, UInt32 nLCID, String bstrWebTemplate, String bstrOwnerLogin, String bstrOwnerName, String bstrOwnerEmail, String bstrSecondaryContactLogin, String bstrSecondaryContactName, String bstrSecondaryContactEmail, Boolean bADAccountMode, Boolean bHostHeaderIsSiteName)
  at Microsoft.SharePoint.Library.SPRequest.CreateSite(Guid gApplicationId, String bstrUrl, Int32 lZone, Guid gSiteId, Guid gDatabaseId, String bstrDatabaseServer, String bstrDatabaseName, String bstrDatabaseUsername, String bstrDatabasePassword, String bstrTitle, String bstrDescription, UInt32 nLCID, String bstrWebTemplate, String bstrOwnerLogin, String bstrOwnerName, String bstrOwnerEmail, String bstrSecondaryContactLogin, String bstrSecondaryContactName, String bstrSecondaryContactEmail, Boolean bADAccountMode, Boolean bHostHeaderIsSiteName)