Hi Developpers When using the dll version of the boost::filesystem library to build a user's dll library, one get the followin link error: (Note that no error is produced at link time when building a static non dll user's library with the boost::filesystem dll library) SYSOUT.obj : error LNK2019: unresolved external symbol "private: void __thiscall boost::filesystem::path::iterator::increment(void)" (?increment@iterator@path@filesystem@boost@@AAEXXZ) referenced in function "public: static void __cdecl boost::iterator_core_access::increment<class boost::filesystem::path::iterator>(class boost::filesystem::path::iterator &)" (??$increment@Viterator@path@filesystem@boost@@@iterator_core_access@boost@@ SAXAAViterator@path@filesystem@1@@Z) Any idea how to solve this unresolved reference?? The code involved in this build is: class __declspec(dllexport) SYSOUT : public OSDDIR { void makedir(const DATASET::VOLUME& volume, const std::string& file); }; void SYSOUT::makedir(const VOLUME& volume, const std::string& file) { path rel(file); path vol(volume); for (path::iterator i = rel.begin(); i != rel.end(); i++) { path dir = vol / *i; if (!boost::filesystem::exists(dir)) { create_directory(dir); } vol = vol / *i; } } Regards Francis ANDRE