Hi there, I was just trying to compile 1.43 on Windows 64 bit for some hours now and unfortunately from my perspective it looks like the modified build system may be a bit broken. First of all, bootstrap.bat didn't work anymore. As usual I was using it to create bjam.exe but this time it just went into causing heavy load and after about 15 minutes it returns telling me the command line is too long. As always, I just did this: ./bootstrap.sh This used to work but not anymore. So I downloaded a precompiled bjam.exe (3.18) and went with that instead. Alas, it created a 32 bit build just fine but failed to produce a 64 bit build. It appears like it is compiling all objects for 64 bit but then tries to link with /MACHINE:X86 , causing the linker to complain: ... common.mkdir bin.v2\libs\math\config\msvc-8.0\debug\threading-multi compile-c-c++ bin.v2\libs\math\config\msvc-8.0\debug\threading-multi\has_long_double_support.obj has_long_double_support.cpp compile-c-c++ bin.v2\libs\math\build\msvc-8.0\debug\threading-multi\sph_neumannf.obj sph_neumannf.cpp msvc.link.dll bin.v2\libs\math\build\msvc-8.0\debug\threading-multi\boost_math_tr1f-vc80-mt-gd-1_43.dll bin.v2\libs\math\build\msvc-8.0\debug\threading-multi\assoc_laguerref.obj : fatal error LNK1112: module machine type 'x64' conflicts with target machine type 'X86' call "C:\Program Files (x86)\Microsoft Visual Studio 8\VC\BIN\amd64\vcvarsamd64.bat" x86 >nul link /NOLOGO /INCREMENTAL:NO /DLL /DEBUG /MACHINE:X86 /subsystem:console /out:"bin.v2\libs\math\build\msvc-8.0\debug\thr eading-multi\boost_math_tr1f-vc80-mt-gd-1_43.dll" /IMPLIB:"bin.v2\libs\math\build\msvc-8.0\debug\threading-multi\boost_m ath_tr1f-vc80-mt-gd-1_43.lib" @"bin.v2\libs\math\build\msvc-8.0\debug\threading-multi\boost_math_tr1f-vc80-mt-gd-1_43 .dll.rsp" if %ERRORLEVEL% NEQ 0 EXIT %ERRORLEVEL% ...failed msvc.link.dll bin.v2\libs\math\build\msvc-8.0\debug\threading-multi\boost_math_tr1f-vc80-mt-gd-1_43.dll bin.v2 \libs\math\build\msvc-8.0\debug\threading-multi\boost_math_tr1f-vc80-mt-gd-1_43.lib bin.v2\libs\math\build\msvc-8.0\debu g\threading-multi\boost_math_tr1f-vc80-mt-gd-1_43.pdb... ... I've tried all sorts of command lines and user-config.jam I could think of, but no effect. Here's what I usually do: ./bjam.exe --architecture=amd64 --address-model=64 -j2 link=shared threading=multi variant=debug,release stage Please let me add that I've been doing this since 1.34 and somehow always managed to get the job done so I have reason to assume there's something that must have changed in this release that broke it. I also tried the switch ---architechture=amd64 and many others I thought might help. I also delete everything already compiled before retrying. The system is Windows XP, current SP and MSVC 8, also current SP. Here's my user-config.jam: ...... using msvc : 8.0 : "C:\\Program Files (x86)\\Microsoft Visual Studio 8\\VC\\BIN\\amd64\\cl.exe" : <setup>"C:\\Program Files (x86)\\Microsoft Visual Studio 8\\VC\\BIN\\amd64\\vcvarsamd64.bat" ; using python : 2.5 ; # Make both versions of Python available using python : 2.5 : "C:\\Program Files\\Python25_64\\python.exe" : "C:\\Program Files\\Python25_64\\include" : "C:\\Program Files\\Python25_64\\libs" : <toolset>msvc ; ....... I also tried to copy the 'tools' folder from 1.42 where it used to work and also the Jamroot and project-config.jam but it still produced the same error. Can anyone give me a hint if there's an issue with the build system in this release? Cheers, Stephan