Move the mouse or trackpad cursor over the center area of the login window so you can see the user icons. Click on the icon of the user that you would like to login as, type in the user's password, and press Return.
If the login window is configured to show only the name and password fields, type in the user's name and password into the fields, and press Return (even if you cannot see the rest of the login window).
This issue will not occur if the display is not sleeping when the account is logged out. Use the steps below to confirm that the account is not configured to log out automatically while the display is sleeping:
1. Open System Preferences > Security & Privacy > General. Click the padlock to unlock the preference pane and enter your admin password. Click the Advanced button at the bottom, then see if the option "Log out after N minutes of inactivity" (where N is the number of minutes) is enabled.
2. Open System Preferences > Energy Saver and configure Display Sleep to occur after the account is logged out, by dragging the slider to a number of minutes that is greater than N was set to in the previous step.
Important: If automatic log out is not needed, disable "Log out after Nminutes of inactivity" in System Preferences > Security & Privacy > General. This will also prevent the issue.
Thanks that screenshot from Apple is exactly what I get. I have to "colour" in the screen to see my log on (we have 4), and click to the password screen which is fine.
I'm a little disapointed I have to say that, all Apple say is to "get on woth it", and disable stuff. I dont want to disable stuff, as I have it to auto log off as it is a family computer with young kids, for us all to use. The options are there for this fucntion to work, so why have them there, if this is an issue?
There was a EFI and WiFi firmware update today, specifying, wake from sleep, for my late 2012 iMac. I've done it so we will see what happens.