Hi, The simple code: std::string str("d:\\New folder"); bfs::path base(str); Is causing an illegal memory access giving the following stack trace: msvcp90d.dll!std::basic_string<char,std::char_traits<char>,std::_DebugHe apAllocator<char> >::assign(const std::basic_string<char,std::char_traits<char>,std::_DebugHeapAllocator<c har> > & _Right="*") Line 1052 C++ msvcp90d.dll!std::basic_string<char,std::char_traits<char>,std::_DebugHe apAllocator<char> >::operator=(const std::basic_string<char,std::char_traits<char>,std::_DebugHeapAllocator<c har> > & _Right="*") Line 927 C++ msvcp90d.dll!std::_DebugHeapString::operator=(const std::_DebugHeapString & __that={...}) + 0x15 bytes C++ app.exe!std::locale::locale<windows_file_codecvt>(const std::locale & _Loc={...}, const windows_file_codecvt * _Facptr=0x18972860) Line 316 + 0x27 bytes C++ app.exe!`anonymous namespace'::default_locale() Line 735 C++ app.exe!`anonymous namespace'::path_locale() Line 777 + 0x2a bytes C++ app.exe!boost::filesystem3::path::wchar_t_codecvt_facet() Line 797 + 0x25 bytes C++ app.exe!boost::filesystem3::path::codecvt() Line 389 + 0x5 bytes C++ app.exe!boost::filesystem3::path::path<std::basic_string<char,std::char_ traits<char>,std::allocator<char> > >(const std::basic_string<char,std::char_traits<char>,std::allocator<char> > & source="D:\New folder", void * __formal=0x00000000) Line 135 + 0x5 bytes C++

app.exe!CDpiExport::configure() Line 188 + 0xe bytes C++

The project is set to use muti byte character support and this hasn't changed in a while I'm sure this was working before and I've reviewed the changes to the project file and I can't see anything that might have broken it. Any suggestions gratefully received. Thanks, M