Copy protection for Windows software for the case “demo version vs. full version”

I have written a software as a student. All functionality was in the software and it was a 30 days fully functional version. After some years there were cracks around and my income was 10% of before. This was where I decided to switch the paradigm to full version vs. demo version with limited functionality (the function weren’t even in the EXE using compiler switches). This in my case ended all piracy and worked very well.

Now you could ask what if a customer uploads his full version to a crack website? For this case I compiled the customer’s full address visibly and invisibly into the EXE file so that I could see which customer was a bad boy…

After some more years I had a new problem: anti virus software. Since my software can set keyboard shortcuts, the heuristic algorithms of some anti virus apps started complaining. So I sent the demo version EXE to the anti virus companies to mark it as “safe”. This worked very well. But only for the demo version which is fixed in bytesize. When I compile the customer’s personal data into the EXE file, the filesize varies a bit and so the checksum differs and the EXE file isn’t marked as “safe” by the anti virus software anymore and the complaining starts again for the customers.

Does anyone have an idea how I could solve this? I can’t add a separate file because this could be deleted by the customer, of course.

Thanks in advance.