MacBook Pro stuck on "Enter Old Password" screen after Big Sur 11.2.2 update
I've just today applied the latest Big Sur 11.2.2 update on my work MacBook Pro (Model 15,1, it's a mid 2018).
I was previously on 11.2.1 and I've never had any problems with other upgrades from Catalina or earlier.
Anyway, after installing the 11.2.2 update and rebooting, macOS asked for my username and password, which I duly entered.
Rather than logging in though, it presented me with a screen as follows:
Enter Old Password
[picture of laptop]
MacBookPro15,1
[computername]
Enter the password you previously used to unlock this MacBook Pro.
Your password is encrypted and cannot be read by Apple.
[password input field]
I entered the password, and then an activity spinner appeared and all the UI controls grayed out.
I thought I'd leave it for a little while, but two hours later it's still spinning away.
This feels like it's too long to actually be doing anything useful, and rather it appears stuck, but I'm a little scared to reboot it, in case it gets even worse.
Additionally, I can't find any answers on Google or DuckDuckGo; nothing comes up for any of the phrases shown in the dialog. Help! Do I just reboot it and cross my fingers that no further problems come up?