Release a version that is also "cracked" and distribute it widely.
Make sure this version breaks after 10 days (so user doesn't suspect) and inserts garbage into whatever it produces after this time.
Ensure your accepted EULA states that if it isn't purchased you can do this of course.
When users also complain of a bug specific to this cracked version, in order to help, ask for their contact details, email and product registration details (in that order). Use provided details if necessary for legal enforcement of licence.
> Make sure this version breaks after 10 days (so user doesn't suspect) and inserts garbage into whatever it produces after this time.
"That software of yours? Yeah, I tried it once and it was garbage, couldn't even save its own output properly. Now you want me to buy it for... wait, how much?"
There are also other games, one whose name eludes me, that deliberately couldn't be completed if it detected it was cracked (and effectively acted as a demo by doing so).
Heard about the first one, but not about FADE, thanks for the link.
If anything, this demonstrates how unpopular this idea is. Of dozens games released and cracked every year, after 40 years of PC gaming, how many tried this strategy? A handful? Also, I now checked some of these games at my favorite torrent tracker, and yes, they are there, they are cracked, and there are no complaints about these defense systems in comments.
And these are games. I wonder if anyone has ever tried that with more useful software, and if they had any success with this strategy.
edit: I now realize I might have met this "in the wild". In my case the game was "The Legend of Kyrandia", and my cracked version could not be completed indeed.
All this trick achieved was making that kid who was me frustrated and unhappy. The game did not explain what was wrong, and there were exactly zero ways I could get a legal copy in Russia in 1999 anyway.
I got a better cracked copy later though. Nice game, do recommend.
