Hi, I just tried RC2 on Cygwin and got the error that is attached to this email. -- VH $ ./tools/jam/src/bin.cygwinx86/bjam.exe -d 2 --toolset=gcc --variant=release --threading=multi --optimization=speed stage Building Boost.Regex with the optional Unicode/ICU support disabled. Please refer to the Boost.Regex documentation for more information (don't panic: this is a strictly optional feature). /cygdrive/c/wilx/cygwin-boost-1_34_0/boost_1_34_1/tools/build/v2/tools/stage.jam:424: in object(installed-shared-lib-generator)@4.run *** argument error * rule virtual-target.register ( target ) * called with: ( object(file-target)@1391 object(file-target)@1392 ) * extra argument object(file-target)@1392 /cygdrive/c/wilx/cygwin-boost-1_34_0/boost_1_34_1/tools/build/v2/build/virtual-target.jam:880:see definition of rule 'register' being called /cygdrive/c/wilx/cygwin-boost-1_34_0/boost_1_34_1/tools/build/v2/build/generators.jam:840: in try-one-generator-really /cygdrive/c/wilx/cygwin-boost-1_34_0/boost_1_34_1/tools/build/v2/build/generators.jam:902: in try-one-generator /cygdrive/c/wilx/cygwin-boost-1_34_0/boost_1_34_1/tools/build/v2/build/generators.jam:1110: in construct-really /cygdrive/c/wilx/cygwin-boost-1_34_0/boost_1_34_1/tools/build/v2/build/generators.jam:1186: in generators.construct /cygdrive/c/wilx/cygwin-boost-1_34_0/boost_1_34_1/tools/build/v2/tools/stage.jam:160: in construct /cygdrive/c/wilx/cygwin-boost-1_34_0/boost_1_34_1/tools/build/v2/build/targets.jam:1242: in object(install-target-class)@65.generate /cygdrive/c/wilx/cygwin-boost-1_34_0/boost_1_34_1/tools/build/v2/build/targets.jam:765: in generate-really /cygdrive/c/wilx/cygwin-boost-1_34_0/boost_1_34_1/tools/build/v2/build/targets.jam:738: in object(main-target)@249.generate /cygdrive/c/wilx/cygwin-boost-1_34_0/boost_1_34_1/tools/build/v2/build/targets.jam:895: in targets.generate-from-reference /cygdrive/c/wilx/cygwin-boost-1_34_0/boost_1_34_1/tools/build/v2/build/targets.jam:1169: in generate-dependencies /cygdrive/c/wilx/cygwin-boost-1_34_0/boost_1_34_1/tools/build/v2/build/targets.jam:1214: in object(alias-target-class)@71.generate /cygdrive/c/wilx/cygwin-boost-1_34_0/boost_1_34_1/tools/build/v2/build/targets.jam:765: in generate-really /cygdrive/c/wilx/cygwin-boost-1_34_0/boost_1_34_1/tools/build/v2/build/targets.jam:738: in object(main-target)@253.generate /cygdrive/c/wilx/cygwin-boost-1_34_0/boost_1_34_1/tools/build/v2/build-system.jam:402: in load /cygdrive/c/wilx/cygwin-boost-1_34_0/boost_1_34_1/tools/build/v2/kernel/modules.jam:261: in import /cygdrive/c/wilx/cygwin-boost-1_34_0/boost_1_34_1/tools/build/v2/kernel/bootstrap.jam:132: in boost-build /cygdrive/c/wilx/cygwin-boost-1_34_0/boost_1_34_1/boost-build.jam:9: in module scope