App protection

I installed a program in a virtual machine, copied the program files to my main system. App runs fine. Included keygen worked, program was happy.

Suddenly, program wants to validate serial, then subsequently locked saying it needs to validate and finally it says I must enter a valid license key.

However, on my virtual machine, the app runs with ZERO problems. I have searched until my eyes bled and cannot find what is on my main system which is giving me a hard time with this app. I want to fully test it before I jump into buying it.

What should I check or should I even bother?

Thanks.