This program fails to compile under msvc.latest: #include <boost/asio.hpp> int main { return 0; } This program does compile: #define BOOST_ASIO_DISABLE_WINDOWS_RANDOM_ACCESS_HANDLE 1 #define BOOST_ASIO_DISABLE_WINDOWS_STREAM_HANDLE 1 #include <boost/asio.hpp> int main { return 0; } Thanks