Q. Can I upgrade the Community Technology Preview (CTP) build of SQL Server 2008 to the release to manufacturing (RTM) build?

A. No. The only supported way to upgrade from the CTP build of SQL Server 2008 to the final build is to uninstall the CTP build then install the RTM build. On the plus side, however, you can attach database files from the CTP build to the RTM build with no problems