how do I enable automatic user login in Yosemite

Same way you did previously.

Open Users & Groups,

Unlock the padlock by clicking on it,

Click Login Options

Select your user from the Automatic login: popup menu.

Go to System Preferences, Security & Privacy and uncheck Disable automatic login:

Open System Preferences, and go to Users & Groups. There should be a Login Options selection on the bottom-left. Click on it, then click on the lock to enable changes to be made. Enter your password, and select your desired account from the drop down menu on the right.

Wishing you the best of luck.

You have to unlock the lock lower left of the dialog window by supplying the admin password.

Look just above your post at the post by joshuakoby. That is a picture of it working in Yosemite.

The screen shot I inserted above was just taken on a MacBook Pro running Yosemite...it is greyed out because to change the setting requires entry of the admin password.

I want to enable automatic login for my (admin) user account. Unfortunately it is not available in the dropdown list. Any suggestions?

I have logged in as Admin and unlocked the lock - the box to enable Automatic Login is still greyed out.

What now?

Heres what I had to do: 1. Go to "Users and Groups". 2. Select the administrator under "Current User". 3. Unlock the padlock at the bottom of the window. 4. Select "Password" at the top of the window. 5. Select "Change Password" opposite the user. 6. In the dropdown window that appears select "Change Password". 7. In the dropdown window that appears enter your old password. 8. In the "New password" space enter either the password that you used for the "Old password" (if you want to keep it) or change it to a new one (your choice), I kept my old one so as to preclude the possibility of having to change it in all my other Apple toys. 9. Then enter the password again to verify. 10. Select "Change Password". 11. Now go back to "Users and Groups", unlock the padlock, select "Login Options" in the "Current user" column and the "Automatic login" option window should now be accessible. Hope this works for you.

Heres what I had to do: 1. Go to "Users and Groups". 2. Select the administrator under "Current User". 3. Unlock the padlock at the bottom of the window. 4. Select "Password" at the top of the window. 5. Select "Change Password" opposite the user. 6. In the dropdown window that appears select "Change Password". 7. In the dropdown window that appears enter your old password. 8. In the "New password" space enter either the password that you used for the "Old password" (if you want to keep it) or change it to a new one (your choice), I kept my old one so as to preclude the possibility of having to change it in all my other Apple toys. 9. Then enter the password again to verify. 10. Select "Change Password". 11. Now go back to "Users and Groups", unlock the padlock, select "Login Options" in the "Current user" column and the "Automatic login" option window should now be accessible. Hope this works for you.

i just had the same problem. i had to go to security and privacy in the system preferences and turn off file vault and now the automatic login button is no longer greyed out

If your disk is encrypted with FileVault, then the OS may insist that you provide a password at login, because otherwise there's no point in having an encrypted disk! 😉