www.makemkv.com

I get an error report of this: "Evaluation period has expired. Please purchase an activation key if you have found this application useful. You may still use all functionality without any restrictions."
Unless I'm blind ( and that thought has occurred to me) I haven't found anywhere to purchase an activation key. For the past year and a half I have used Makemkv with no problem whatsoever, but since the first of the year I keep getting the above messages no matter how many times I uninstall and re-install the program.

thank you. you helped me

The evaluation period is only reset when you enter a "new" beta key, or put in a purchased permanent key.

"New" is in quotes because it can be the same beta key as is in the program already, it's the action of doing it that resets the 30-day counter.

Both the beta key and permanent key are inserted using the Help->Register menu, which is right below Help->Purchase... the link you were missing. That link will take you to https://makemkv.com/buy/ and the payment processor Mike uses for buying keys.