Back in January Microsoft encrypted all my hard drives without saying anything. I was playing around with a dual boot yesterday and somehow aggravated Secureboot. So my C: panicked and required a 40 character key to unlock.
Your key is backed up to the Microsoft account associated with your install. Which is considerate to the hackers. (and saved me from a re-install) But if you’ve got an unactivated copy, local account, or don’t know your M$ account credentials, your boned.
Control Panel > System Security > Bitlocker Encryption.
BTW, I was aware that M$ was doing this and even made fun of the effected users. Karma.
Disk encryption should absolutely be used, especially on laptops/portable systems.
Otherwise someone steals your laptop and swaps the disk into another system and they’ve got all your stuff. Including that folder that nobody knows about.