Block WLM, Windows Live Messenger

Can anyone help me how to block traffic for WLM Messenger? I read before and i tried some rules but none is good since i can’t block wlm without affecting the other traffic, i.e. https traffic.
Please help

You can’t do this without a proxy that has a certificate trusted by all users so it can transparently intercept HTTPS traffic. In short, you can’t do this on RouterOS.