I've got this message after running a bjam warning: mismatched versions of Boost.Build engine and core warning: Boost.Build engine (bjam) is 03.1.19 warning: Boost.Build core (at I:/boost-trunk/tools/build/v2) is 2011.04-svn Should I worry about this? I've tried to re-build using I:\boost-trunk\tools\build\v2\engine>bjam --toolset=msvc >build_bat.log but it still complains ### No toolset specified. Please use --toolset option. Is this supposed to be --toolset=msvc or --toolset msvc Suggestions? Thanks Paul PS This bit of the doc didn't seem right be me "For the Boost.Jam source included with the Boost distribution the jam source location is BOOST_ROOT/tools/jam/src." and was suggesting running build.bat I:\boost_1_46_0\tools\build\v2\engine\src contained build.bat and build.jam --- Paul A. Bristow, Prizet Farmhouse, Kendal LA8 8AB UK +44 1539 561830 07714330204 pbristow@hetp.u-net.com