Thanks, I was able to reproduce the issue. It only reproduced when I closed the socket instantly after sending the data. I have tested two fixes: the first checks for WSAECONNRESET errors on UDP sockets and ignores them. The second applies SIO_UDP_CONNRESET to the socket. Both seem to work. Which do you think would be best in this situation? As mentioned here, with UDP the error is not due to a connection reset but to reachability. So either method sounds like it should work correctly.