Hi, I recently tried to build boost 64bits on an intel EM64T (core 2 duo) with msvc. And bjam incorrectly selected the x86_amd64 toolset (cross compiler) instead of the amd64 one (native 64bits compiler). In the file boost/tools/build/v2/tools/msvc.jam at the line 314 the check is: if [ MATCH ^(AMD64) : [ os.environ PROCESSOR_IDENTIFIER ] ] should it be if [ MATCH ^(AMD64) : [ os.environ PROCESSOR_ARCHITECTURE ] ] or if [ MATCH ^(AMD64) : [ os.environ PROCESSOR_IDENTIFIER ] || MATCH ^(EM64T) : [ os.environ PROCESSOR_IDENTIFIER ] ] (not certain about the syntax) My os environement are: PROCESSOR_ARCHITECTURE=AMD64 PROCESSOR_IDENTIFIER=EM64T Family 6 Model 15 Stepping 6, GenuineIntel Regards, Ps: perhaps I should post this on boost.build ? -- Cédric Venet