Get a username and password prompt when you only have a user list

Say you want to login as root or the administrator and you only have a list of users. Most experienced Mac users know the machine is full of keyboard shortcuts and this little shortcut can come in handy.

Option, Up Arrow, Enter will bring up the username and password prompt if the login window only has a list of users. This will allow you to login as a user not listed like root or local admin.