Ok. I just made myself look like an idiot! I forgot how literal and procedural C++ was! Solution: serial_port uses io_service in its constructor. Since C++ instantiates class members in the order in which they are declared in the header file, I simply had to move the declaration of the io_service above the declaration of the serial_port in the header file. I slowly stepped through debugging to confirm that nothing was breaking, and when it looked like I was in the clear, I cleared all breakpoints and restarted the program. Result: Success! Wow am I an idiot! Thanks anyway. -- View this message in context: http://boost.2283326.n4.nabble.com/Access-violation-when-setting-up-a-serial... Sent from the Boost - Users mailing list archive at Nabble.com.