Ask Different is a question and answer site for power users of Apple hardware and software. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I leave my iMac (24') next to the sliding door in the lounge at night. The door remains open, so the air gets very cold at night. When I turn my computer on in the morning the screen fogs up inside, presumable because of the cold air inside warming up quite suddenly from the heat of the LCD.

Is there an easy fix, or a way to avoid this happening?

share|improve this question
Close the door ? – Studer Aug 27 '10 at 6:11
I gotta say this made me chuckle… – Martín Marconcini Aug 28 '10 at 0:57
up vote 2 down vote accepted

Consider the operating temperatures of the iMac and see if you’re not going beyond the limits. Electronics cannot (and shouldn’t) be operated beyond temperature limits. As much as heat is bad, extreme cold is not good either.

As already suggested, do not expose your iMac to “very cold air at night”.

share|improve this answer

I have seen this all the time in Minnesota when macs are cold much of the year. The blowers kick up air that condenses on the cold glass - especially at the bottom of the screen.

As long as it's not condensing and goes away within minutes - it should be fine. If you are worried, best to keep it running and warm or find a way to keep the area around the mac warmer.

share|improve this answer
we need a giant, fuzzy, imac-shaped sock – Nathan Greenstein Jul 16 '11 at 1:38
Oh man - i know just the person to yarn bomb an iMac. – bmike Jul 16 '11 at 3:45

I was having a similar issue when bringing my screen in from a colder temp indoors and turning it on immediately. This worked:

Turn off the display (or shut down the mac if the display is integrated), then leave it for 15-30 mins. The display will defog and get acclimated to the temperature. Then you can safely turn it back on again and it will not fog up.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.