Hi, All! BOOST_CLASS_EXPORT_GUID macro failed to compile with error: error C2888: 'boost::archive::detail::`anonymous-namespace'::init_guid<CSomeClass>' : symbol cannot be defined within namespace 'anonymous-namespace'. Same code compiles properly using boost 1.37. Looks like a bug to me. Using: - boost 1.39 - Microsoft Visual Studio 2008 SP1