Can't help with the requirement to re-purchase Enpass, but I was able to successfully upgrade to premium on my Windows 10 (64-bit) machine by doing the following: 1. Open the Microsoft store app 2. Click on your avatar in the top right. 3. Sign out of your account in the store 4. Go back to Enpass and click "Buy" a window should open asking about your account 5. DO NOT click your account - instead choose "Use a different account" 6. Enter your email address -> then press continue 7. Enter your password -> then press continue 8. After this I was able to complete the purchase Hopefully this works for you!