www.makemkv.com

I downloaded yesterday version 1.10.8, and was able to use it once.
Today, I get "Evaluation version expired - disc open failed"
What can I do?
The makemkv web page says that the evaluation version is valid for 30 days...
Also, I don't see how to buy the linux vesion.

Current beta key is always available here: http://www.makemkv.com/forum2/viewtopic.php?f=5&t=1053

which you can apply via 'Help > Register' (from the menu bar).

And we always encourage folks to purchase a key to support the cause:

'Help > Purchase' (from the menu bar) takes you to: /buy/