I've downloaded Boost 1.43.0 and used bcp with the --namespace and --namespace-alias options to prevent link conflicts with other third-party libraries in our project at work. It does appear that some unwanted text substitution is happening (causing compile failures), after renaming the boost namespace. For example, in type_traits/integral_promotion.hpp, the original header guard is: #ifndef FILE_boost_type_traits_integral_promotion_hpp_INCLUDED #define FILE_boost_type_traits_integral_promotion_hpp_INCLUDED After running bcp, the header guard is: #ifndef FILE_boost_type_traits_integral_promotion_hpp_INCLUDED #define FILE_MyProj_Boost_type_traits_integral_promotion_hpp_INCLUDED "MyProj_Boost" is the namespace replacement option as supplied to bcp. There are three files in type_traits with this problem, all with : integral_promotion.hpp promote.hpp floating_point_promotion.hpp It looks like these three header files are the only ones with lower-case header guards (all with copyrights by Alexander Nasonov). I've never filed a trac bug report, but will be happy to, if requested. I assume the easy solution is to make the three type_traits files consistent with the other header files, but is this something that bcp should be handling? There's other compile failures I'm working through, but thought I would start with this one. As always, thanks. Cliff