Blackbaud's default SQL Server 2008 R2 Express Edition installation uses Mixed Mode [SQL Server and Windows] authentication.

Blackbaud does support our software on a full version of SQL Server using Windows Only authentication mode. In this case the SQL Server administrator must give the required rights for users to access the server.

In regards to SQL Server Standard/Enterprise, Blackbaud does not recommend either authentication method (Mixed Mode or Windows Only), since this setting affects all databases attached to the SQL Server instance. Please consult your SQL Server administrator in regards to making this decision.