Dark "smudges" are appearing at the top of my iMac under the screen.

Change your desktop picture to an all white background then take a picture.

Okay, I see them, if your machine is under warranty I would take it to your nearest Apple store to have them take care of it. If it is not under warranty you can clear it yourself, the glass screen lifts off with some suction cups. Just be aware that cleaning LCD screens can be difficult if you never done it before, you could actually make it worse.

My October 2010 27" is showing signs of this all over the monitor/TFT.

Would it be worth taking it to my nearest (80miles) Apple Store to have them take a look at it?

I also have, what appears to be, dust trails emitting from the top left/right hand corners of the screen in a fan shape pattern?

Message was edited by: Digital-Prozac

I have recently developed the same problem. (Dec '09 27" quad core iMac). With the aid of youtube I tried the suction-cup method to remove the glass fronting to clean underneath which turned out to be inneffective and therefore proved to me that the smudges are developing inside the LCD itself or behind it. I'm not brave enough to try and dismantle the machine any further.

I've also searched around and this complaint seems disturbingly common with this model. I'm not happy! For a premium computer that is sold primarly based on the display/size/resolution/aesthetic it's shocking that this problem is happening to quite a few people and for many ruins the machine.

I've heard on other threads/forums people blaming environmental factors (excessive dust or pollutants) and heat/condensation as a probable cause... but in my case and I suspect many others this is not abnormal and there is no excuse considering this has never happenned before with any other device/computer that I own or have owned.

I have the same issue with my 21.5" Core2Duo iMac. Hoped it was the cover, but it's the LCD. As a Mac user since 1985, i'm also very disappointed. I didn't buy the Apple Care Warranty because when you pay a premium for a quality product, you don't expect it to have quality issues shortly after the warranty expires (this has been getting worse for months but I only brought it up to Apple after the warranty expired).

I had the same problem on a refurb 27". Under warranty, AppleCare, and they authorized a replacement for me. Took 2 weeks, but I'm so happy to have it back. Always buy the AppleCare and assume that's the short life and if you get a good one, you're set for 5-8 years.

I'm having the same issues with the LCD screen. It's showing gray smudges top center of screen and what looks to be light rays extending down a couple inches.

Took it to Apple store in Philly and they won't repair for free since I'm 3 weeks past warranty. The manager said "he's sorry but I should have gotten Apple Care, and he has to enforce the one year cut off date".

That said, it will cost $439 to replace the LCD.

C'mon Apple. Highly dissapointed. This machine is only a year old! ***!!!!!

21.5 inch iMac mid-2011