Hi, I wrote earlier about linking problems with Boost & Microsoft VC8 beta 2. I realized I hadn't built Boost with VC8, I thought I did but apparently the build system was confused by the fact that both Visual Studio 2003 and 2005 where installed and defaulted to the older version. I was finally able to build renaming the Visual Studio 2003 folder. I was suprised to see that the Boost Serialization library was correctly built only in the release version, the debug version reported compilation errors. I've narrowed them down to actually the _DEBUG macro being defined or not. When it is defined compilation errors appear when compiling for example xml_grammar.cpp I'm using the v1 build system as I wasn't able to understand how v2 works, I managed only to make it build a dll version of the Serialization lib. Follows is a command line that compiles the file. Switching from /MD to /MDd breaks the compilation. /MDd /U_DEBUG works, as it undefines _DEBUG. C:\swap\boost2\boost_1_32_0\libs\serialization\build>"c:\Program Files (x86)\Microsoft Visual Studio 8\Common7\Tools\..\..\VC\bin\cl" /Zm800 -nologo /EHsc -c -DBOOST_TEST_NO_AUTO_LINK=1 /MD /Z7 /Od /Ob0 /EHsc /GR /Zc:forScope /Zc:wchar_t -I"..\..\..\bin\boost\libs\serialization\build" -I"C:\swap\boost2\boost_1_32 _0" -Fo"..\..\..\bin\boost\libs\serialization\build\libboost_serialization.lib\vc-8_0\debug\threading-multi\xml_grammar.obj" -Tp"C:\swap\boost2\boost_1_32_0\ libs\serialization\build\../src/xml_grammar.cpp" Needless to say I'm lost. Thanks to anyone who could shed some on this. Flavio.