MakeMKV not working on Mac

[KJ-98]

When opening the app I get the following error message: This application version is too old. Please download the latest version at http://www.makemkv.com/ or enter a registration key to continue using the current version.

However, I already have the latest version MakeMKV 1.17.7 for Mac OS X on both of my macs
I removed it and downloaded and installed the latest version again via your website. However, I keep getting this message and the program is unusable.

What can I do to fix this, or is the problem with the program itself?

[Woodstock]

You have not mentioned whether or not you put the current key in; your description looks just like you started the program with the multi-month-old key that is in the original archive.

MakeMKV is free while in beta