Windows 10 gets automatically activated?

[ian87w]

Quick background: 2012 mac mini, Catalina, never installed Windows 10 on it ever.
I decided to install Windows 10 via Bootcamp. Did everything according through instructions. When booted to Windows 10, I set up an offline account (wifi didn't work anyway at first boot setup). I didn't put in any serial, and picked Windows 10 Pro. After everything's set up, and online, I checked the activation, and it said Windows has been activated with a digital license. This is with that offline account, and I have not logged in into my Microsoft account.

Did Microsoft just freely activate my new Windows 10 installs?

I set this up the same as how I usually set up any new Windows machine. And usually Windows will be in the "trial mode" until activated properly with a license. Very weird... Not complaining though, and I do have valid licenses ready anyway.

 

[ian87w]

After some googling, seems I found out the answer. I'll share it here.

Activate Windows - Microsoft Support

Learn how to activate Windows using a product key or digital license, check your activation status, and link your Microsoft account.

support.microsoft.com

Apparently when a Windows 10 machine with certain types of licenses has ever been activated successfully in the past, Microsoft stores its unique ID, so when a reinstall happened, that machine will automatically reactivated without any need to re-enter any keys. I'm guessing the previous owner of my mac mini probably had had Windows 10 installed on it, so now it just reactivates on its previous digital successful digital license.

How neat.

 

[MBAir2010]

my Dell XPS 13" had no problem going back to Windows 10 this autumn.
windows seems to be more user friendly and easier in that aspect of upgrading and downgrading.