I’m sure this has been asked before, but is it possible to install Renoise on 2 different machines with the same product key?
I R n00b.
Renoise license is personal. this means that you can install it on any number of machines, provided that you are the only person using Renoise on them
Ah ok, awesome.
Cheers 
Meaning, no one else has access to your copy.
Installing on your personal computers in your own room:yes
Installing on a machine in an internet cafe or on your work office or even on your friends computer:no!
And please keep it that way!
Ive got it on my mac, and my PC, works great this way, I do a lot of reinstalls and I love how easy it is to download renoise again. ^^