Can't Enter Password

I used the userpasswords2 method to set an autologin for my primary user
account, which works fine. But if I then log off, and go to log back into
the same account, or to my admin account, both of which require passwords,
the password box pops up, but no text from the keyboard is entered. The
mouse is working at this point (as is the keyboard, as it is lit up and
all), but no key I enter causes any text to appear in the box, and I cannot
login. I have to shut restart the computer to get back in.

The keyboard is USB, but it works fine otherwise, even when first booting
the machine. So why isn't the keyboard input being used for entering the
password?

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Regards,

Rick Raisley