Hi,

Your first message is a little confusing, implying that you received an upgrade from 17 to 18.

Just to confirm, you installed and activated XDP18 a couple of days ago, and then you received an update notification (patch) which you downloaded and installed (automatically). Then, the box popped up for the email and serial number. I'm surprised that you had to re-enter the serial number. Normally, the SN shows up with your email address by default when you install a patch, and you just accept it. It is a form of validation, that is all.

Is this what happened?

Or, this is the first installation of XDPX18 and the SN box was empty. If so then that is normal because you would have received a new SN and the program doesn't know what it is.