I'm not sure Win 10 is the cause... I've had Topaz installed on my Laptop (Win 7) for ages before upgrading to Win 10. It still runs fine. I believe Topaz can only be installed on a maximum number of 2 devices (that's what it says on the website). Perhaps that's why? I'm not sure how to fix it though. Maybe you need to uninstall from one of them, or buy another set of serials? Sorry I can't help much.