So, it happened that a friend of mine turned off Bluetooth on her Mac mini, and then turned it off for the evening. When she got up the next morning, her Bluetooth keyboard was on, as per usual, but she couldn’t log in on start up, as her Mac did not see her keyboard.
She was worried that she’d have to go borrow or buy a wired keyboard, plug it in, and enter her password, then turn Bluetooth on again to make her wireless keyboard work again.
Luckily, that’s not what had to happen. Here’s how we solved it.