Is WSUS compatible with SQL Server 2005?
SQL 2005 (any edition) is not a supported environment for WSUS 2.0. Officially WSUS is not supported on SQL Server 2005 by Microsoft, at this time.
However, I have seen some folks in the community successfully installing WSUS 2.0 on SQL Server 2005. It’s an “unsupported” configuration at this time. It is recommended to install WSUS on SQL 2000 instead of SQL 2005.