Hi When using debug mode in windows with boost_filesystem there's "Debug Assertion Failed!" in _CtrIsValidHeapPointer When operator new is redefined it causes windows_file_codecvt not to be released with the matching release that it allocated it. We reported this to Microsoft as seems it's a bug in their STL. But so far, I tried with VS2012 and the bug seems not fixed... There's a workraround in boost that we are using for the moment: This has to be changed in path.cpp to fix it: - std::locale loc(global_loc, new windows_file_codecvt); + std::locale loc(global_loc, _NEW_CRT windows_file_codecvt); Should this fix be applied in boost until is fixed on Microsoft's side? This is a very nasty issue that will happen only with a redefined operator new. (For example we are using new with the sacalable allocator of tbb). Regards. Pedro.