Odd problem on one of the Macs here ... on reboot the user accounts didn't show on the login screen, only the admin. It would appear if we used the Log Out command though, which was strange.
The problem turned out to be with FileVault, and the fix was painless.
- Open System Preferences
- Choose Privacy & Security
- Click on FileVault
- Click the Enable users... button in the preference pane and enable the user account you want to show on the screen. That users will need to enter their password to do this.
On reboot the users should show up on the login screen.