I just did a fresh install of OS X El Capitan. However, I tried enabling automatic login, but it stays locked. It was frustrating.
- Go to System Preferences, select Security & Privacy to turn off FileVault for the disk.
- Go to Users & Groups and click Change Password
- Instead of using my iCloud password to log in and unlock this Mac, choose to use seperate password.
- Set my new password
- Click Login Options and enable automatic login for my account.
Yay, it worked out!