I am attempting to build the complete boost library set with the command line: bjam -sTOOLS=msvc-stlport "-BUILD=debug release <stlport-iostream>on" Unfortunately, 5 of the release DLLs fail to link with the following error: unresolved external symbol "public: static void __cdecl _STL::_STLP_mutex_spin<0>::_M_do_lock(long volatible *)" ("_M_do_lock@?$_S_STLP_mutex_spin@$0A@@_STL@@SAXPCJ@Z) What is confusing is that the debug DLLs all build with out a hitch! I am using MSVC 6.0 SP5, STLport-4.5.3, and Windows Platform SDK - Nov2002. Any help would be greatly appreciated!! --Jamie