I’d been working on my new Mac mini and everything was fine. Used an old, wired keyboard and my Pi 400 mouse for the initial set-up, then registered my Bluetooth mouse and keyboard.
Set up FileVault to encrypt everything. It all looked fine…
Then I rebooted. Nothing. I can’t log on. Mouse and keyboard refuse to work.
Rummage through my parts box and dig out the wired keyboard again, plug it in, type in password and it logs on and the Bluetooth mouse and keyboard suddenly start working again! It turns out that, if you use FileVault, Bluetooth mice and keyboards are disabled until you have entered your password! (Apple own-brand mice and keyboards excepted, for any other brand of keyboard and mouse, it seems to be pot-luck, whether they will work or not.)
I’ve now switched off FileVault, but that is a real pain.
It looks like I need to get a wired (or something like a Unifying Adapter based) keyboard and mouse. But I don’t really want to fork out another 120€ for a new keyboard (the only wireless, non-Bluetooth ergonomic keyboard I could find was the Logitech Ergo K860). At least the mouse is BT and Unifying, so I would just need an adapter for that.