[UPDATE] As of the latest 10.13.2 beta (beta 3) Tap to Unlock has been fixed by Apple. Let’s hope it stays like that! Thanks to Katia for letting me know so quickly 🙂
Unfortunately something has changed on macOS that has caused apps that access the trackpad (MacID and Better Touch Tool) to stop working. I’m looking into if it’s fixable but I haven’t found a solution yet.
Please avoid updating to 10.13.2 if you rely on Tap to Unlock because I cannot guarantee it will keep working.