Hi, as mentioned on the Boost user mailing list a week ago (http://thread.gmane.org/gmane.comp.lib.boost.user/82429), I cannot build Boost from develop anymore. I just noticed that I can still build individual libraries, only the combination of Boost.System + Boost.Endian (and thus building all of Boost by just running "b2") is broken. "b2 --without-endian" works, "b2 --without- system" doesn't. Does anyone have any idea what the problem could be? The output of "b2 --with-system --with-endian" is: K:/boost/tools/build/src/build\virtual-target.jam:1099: in virtual- target.register-actual-name from module virtual-target error: Duplicate name of actual target: libboost_system-vc140- mt-gd-1_57.lib error: previous virtual target { common%common.copy-libboost_system-vc140- mt-gd-1_57.lib.STATIC_LIB { msvc%msvc.archive-libboost_system-vc140-mt-gd -1_57.lib.STATIC_LIB { msvc%msvc.compile.c++-error_code.obj.OBJ { error_code.cpp.CPP } } } } error: created from ./stage-proper error: another virtual target { common%common.copy-libboost_system-vc140-mt- gd-1_57.lib.STATIC_LIB { msvc%msvc.archive-libboost_system-vc140-mt-gd- 1_57.lib.STATIC_LIB { msvc%msvc.compile.c++-error_code.obj.OBJ { error_code.cpp.CPP } } } } error: created from ./stage-proper error: added properties: <asynch-exceptions>off <warnings>on error: removed properties: <asynch-exceptions>on <warnings>all K:/boost/tools/build/src/build\virtual-target.jam:484: in actualize-no- scanner from module object(file-target)@3811 K:/boost/tools/build/src/build\virtual-target.jam:134: in class@virtual- target.actualize from module object(file-target)@3811 K:/boost/tools/build/src\build-system.jam:720: in load from module build- system K:\boost\tools\build\src/kernel\modules.jam:289: in import from module modules K:\boost\tools\build\src/kernel/bootstrap.jam:139: in boost-build from module K:\boost\boost-build.jam:17: in module scope from module