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I have the same problem. But it only appears to happen when using lightroom. Once I reboot it goes away. Is it a graphics card glitch that can be resolved with an update? Not sure?. It does not happen when I am using bootcamp.

If a reboot solves the problem, then it's not image retention. Something else is going on.
 
I've got the same problem with my 2012 26" refurbished BTO. I noticed it as soon as I finished setting up the machine for the first time, as the window from the setup prompts remained visible on the grey background of the login screen. My attempts for an easy solution through AppleCare turned out to be a futile attempt, as they ended up requiring me to bring the computer into an Apple store so they could "confirm" the issue. I'm wondering how the rest of you who have gotten them to agree to a replacement have done so without having to first bring it into a store? Also, as far as I know, they will first require it to be repaired, not replaced immediately, which to me, is unfortunate, seeing as this is my work machine and I'd prefer not to have its life begin with a repair done by some guy in an apple store, not to mention the down time, waiting for them to repair it.
 
This is not normal. Contact Apple and I'm sure they will fix it.

I have the Late 2012 iMac. I have no screen issues at all with it.
 
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