I already know one license is only for one machine, however I currently have Leopard UTD installed on my Mac Mini (I bought it recently), but would rather have Leopard on my MBP (which I purchased months ago with Tiger). Since I already registered Leopard with my Mac Mini, am I able to remove it and put Tiger back on it, and then install Leopard on my MBP? Or once registered, am I not able to switch? How does Apple determine whether only 1 license is being used at one time? I am not going to attempt to install my Leopard on both machines, I just want to transfer it to another one.