Hi all, I am having trouble building Boost 1.55 for x64 using VC12. 32-bit builds without error, but 64-bit fails. All of the errors are boost/archive/iterators/transform_width.hpp(151) : error C2039: 'min' : is not a member of 'std' and repeats a lot I added #include <algorithm> to the beginning of the transform_width.hpp header file, and the build now completes without error. However, my app has two linker errors linking with libboost_system-vc120-mt-1_55.lib features.obj : error LNK2019: unresolved external symbol "class boost::system::error_category const & __cdecl boost::system::system_category(void)" (?system_category@system@boost@ @YAAEBVerror_category@12@XZ) referenced in function "public: __cdecl boost::system::error_code::error_code(void)" (??0error_code@system@boost@ @QEAA@XZ) features.obj : error LNK2019: unresolved external symbol "class boost::system::error_category const & __cdecl boost::system::generic_category(void)" (?generic_category@system@boost@ @YAAEBVerror_category@12@XZ) referenced in function "void __cdecl boost::system::`dynamic initializer for 'errno_ecat''(void)" (??__Eerrno_ecat@system@boost@@YAXXZ) Again, the 32 bit builds and links Ok. I'm thinking that as the problematic file in Boost in is an 'archive' directory, perhaps the wrong include file is being picked up? But I can't find the difference in 32/64 configurations to find the cause. Is this a known problem? Any suggestions how to diagnose or (preferably!) fix this? Many thanks Craig