Quick summary: I had the notorious grey smudges and brought my iMac into an Apple store. They confirmed the issue and replaced the computer with a new one. I am still under my 1 year manufacturer warranty. This all took place two weeks ago.
Specs: 2011 iMac 27/2.7QC/2X2GB/1TB/6770M
Details:
I purchased my iMac in August 2011. Note that as of this posting I am still under the 1 year manufacturer warranty. A few months ago I started noticing the grey smudges that are so accurately described in the thread. I was hesitant about bringing my iMac to the Apple store, because I was afraid they wouldn’t be any help and I would end up getting put off. Lucky for me, the nearest Apple store is within walking distance of my place. So I finally made the genius bar appointment and brought it in. After being met with, I described the problem and the iMac was taken into the back. After a bit the rep came back out and said they see what I am talking about and they think the “Pixels are dying”, I said okay… (There was no point in arguing with him, I think its dust but I really can’t say definitively what it is or why it is.) The rep went into the back room again and when he came back he started asking when I bought the computer. I told him the exact date and he pointed out that it is under the 1 year warranty so they should be able to fix it for free. He left again and when he came back he started asking very specifically “When did you first notice this issue”, I was hesitant to just blurt out an estimate, because in situations like this there is normally a right and wrong answer. I said that I can’t be sure exactly when I first saw it, because for a while I was mistaking it for a smudge on the glass. I asked him why the exact time I first saw it was important. He said that if I saw it within the first four months of buying they would have to replace the whole computer, if I saw it after that, they would send it in for repair. Hearing that, I responded by saying that it was definitely within the first four months, but I am not sure of the exact day. He didn’t have a problem with that, and said regardless, this is not the first time they have seen this issue and that Apple is interested in ‘Capturing’ the computers that are displaying the problem for further examination. I ended up bringing my computer back home before turning it in, so that I could take a full backup and write zero’s to the HD. When I brought it back they swapped it out for a new, still in the box iMac 27/2.7QC. I even got a new mouse and keyboard out of it as I had not turned mine in. In order to corroborate this story, I am considering uploading a copy of my genius bar receipt, and a work order receipt that I made the rep write up stating that they were going to replace the machine. If anyone is interested let me know.