Why is Automatic Login greyed out in Login Options

Is the drive encrypted? you need to enter a password to decrypt, so the user login password serves both purposes.

If the drive is encrypted, you cannot auto-login, because then the drive would be always decrypted.

Is the Current User field show an "admin" user or "standard"?

Is the padlock at the bottom left open or closed? To open the lock on the Users & Group pane before making any changes - just click on the padlock at the bottom right and enter your password. If it doesn't unlock then you didn't enter the correct password. Then click on the "Automatic Login" field and select the user that you want to be automatically logged in when the system boots.

You might want to have a screen saver with password so nobody can get easy access to your computer. Another thing to beware is that simply turning off and back on the system will allow anyone access to that account. So keep that in mind. Perhaps the computer is located in a place that no one has physical access so that is not a concern?

Good luck...