Hi, guys! I had following problem when using boost::filesystem dynamically linked on windows platform: unresolved external symbol boost::filesystem::not_found_error. (By the way, this issue was raised up on users list some time ago, but had no resolution). According to dumpbin utility, mentioned symbol resides in boost_filesystem binary, so, I guess, there is some problem with macro magics (__declspec(dllimport/dllexport) ) in header file (operations.hpp). I'm building test application using Boost.Build: Boost.Build V2 (Milestone 11) Boost.Jam 03.1.16 and boost 1.34.1. Compiler is MSVC 9, but problem is reproducible on MSVC 8. The attached patch fixes the problem by defining BOOST_FILESYSTEM_DYN_LINK in usage requirements (in boost.filesystem's Jamfile.v2), but I'm wondering 1. why all the other symbols are successfully imported when mentioned macro is not defined 2. and why this macro wasn't defined in usage requirements by the author of the library. Could you please shed a light on this issue or correct me if I'm doing something wrong. Thanks. Sasha P.S. In attach there are minimal project that reproduces the problem and patch that fixes the problem.