Misty screen

condensation inside the glass, if i were to guess. was it cold in your home or very warm in your home while you were gone? there are videos on YouTube on how to take off front Glass to clean inside screen. But if it went away, i think your good for now. Be sure the glass on screen is flush & tight against the iMac body.

There have been tons of report of this with 24" iMacs too (sometimes only on arrival, sometimes recurring). It usually goes away without leaving stains, otherwise you can clean inside the glass as the post above did suggest (basically just pull away the front glass from it's magnets using suction cups, e.g. a bathroom towel holder or similar).

If you don't have any suction cups, you can use a bit of parcel tape, just lightly stick a bit to one edge and pull, the glass will easily come away from it's magnets and doesn't leave any residue.

you can also use the Suction cup part from a GPS. Put it on top right (or Left) corner & it should come out. Doing it from Top, keeps your screen on the small Lip on Bottom , So Screen Does Not Fall.

If you're going to remove the glass, you MUST prep the room to be low-dust. Because of the iMac's design, the gap between the front of the LCD and the back of the glass means that circulating specks of dust WILL stick to either surface at random and create blurry pixels. Even if you think you've cleaned both surfaces and quickly replace the glass, it can take several hours for introduced particles to stick.

I've experienced this nightmare with an iMac in the past and I absolutely wish I had not followed the glib advice to "just remove the glass".

A can of compressed air helps to reduce this, i've done it a few times on various iMac's usually when people have wanted the hard drives replacing.

I have been away for a few days over christmas and I when I returned and switched on my 24" iMac the screen appeared with mist on it, the mist didnt seem to appear until I had the computer on for approx 30-40 mins. I have spoken with a friend who has an iMac and he has informed me that a friend of his had the same problem and Apple replaced his iMac immediately. My iMac will be 12 months old on 6th Feb so I am coming close to the end of the warranty.

Has anyone else experienced this and managed to get a replacement iMac from apple?

Regards
Neill