So, I rebooted my Windows laptop after some update, and was greeted by this surprise!

I guess lucky for me I had the machine tied to a Microsoft account which in turn had the key backed up. After some tedious typing later and I was back in business.

I guess this was the culprit?

BitLocker was so transparently well working I didn’t even know it was even running. Got to give it that much credit. And if anything, probably should just give up and run it everywhere.