Hello, I'm a boost newbie, so please bear with me if this sounds trivial. I'm rebuilding our code that uses boost heavily with VC 9.0 on Windows 2008, 32-bit. All of our code is compiled with _SECURE_SCL=0 & _HAS_ITERATOR_DEBUGGING=0. And I rebuild boost with the same flags. Our code links with boost as static libraries. However, at runtime - I'm seeing access violations occuring in the Microsoft secure STL code that should have been disabled with _HAS_ITERATOR_DEBUGGING=0. A specific example, when we call filesystem::basic_path::normalize(), this calls: // path.hpp template<class String, class Traits> void basic_path<String, Traits>::m_append_separator_if_needed() { if ( # ifdef BOOST_WINDOWS_PATH *(m_path.end()-1) != colon<path_type>::value && # endif // >>>>>> following is the offending line *(m_path.end()-1) != slash<path_type>::value ) { m_path += slash<path_type>::value; } } which leads me to: //xtring reference __CLR_OR_THIS_CALL operator*() const { // return designated object #if _HAS_ITERATOR_DEBUGGING if (this->_Mycont == 0 || _Myptr == 0 // >>>>>> following is the offending line - _MyCont contains garbage || _Myptr < ((_Mystring *)this->_Mycont)->_Myptr() || ((_Mystring *)this->_Mycont)->_Myptr() + ((_Mystring *)this->_Mycont)->_Mysize <= _Myptr) { _DEBUG_ERROR("string iterator not dereferencable"); SCL_SECURE_OUT_OF_RANGE; } __analysis_assume(_Myptr != 0); #else if (this->_Mycont != _IGNORE_MYCONT) { _SCL_SECURE_VALIDATE(this->_Has_container()); _SCL_SECURE_VALIDATE_RANGE(_Myptr < (((_Mystring *)this->_Mycont)->_Myptr() + ((_Mystring *)(this->_Mycont))->_Mysize)); } #endif /* _HAS_ITERATOR_DEBUGGING */ return (*_Myptr); } I'm stumped as to why its even in that piece of code when I've disabled HAS_ITERATOR_DEBUGGING. Any help/guidance is appreciated. Thanks Raman