Why won’t my iMac switch on for an hour after an extended time of being shut off?

Andrew Taylor January 15, 2011
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If I shut down my iMac for a few days, upon return it refuses to switch on for about an hour! I have tried starting up pressing “x” “shift” and all the usual combos, unplugging everything and resetting PRAM and the like, all to no avail. Eventually it decides to kick in! All I get is the brief wirr for one second and then an immediate wheeze of the hard disk presumably winding down.

  1. Jonn200
    November 1, 2011 at 5:46 pm

    Im having the same problem.  What was the solution and what was causing the problem?


  2. Chips Chapman
    January 20, 2011 at 6:54 pm


    You state that the iMac was bought last Christmas. Do you mean ~ a month ago? Contact Apple. It's still under warranty. Even if it was Christmas 2009, contact Apple. It may still be covered under warranty. I suppose you did not get AppleCare?


  3. Mike
    January 15, 2011 at 9:34 pm

    Is it an Intel iMac (aluminium) or an older PowerPC model (white plastic)?

    And what do you mean by it refuses to switch on:
    Do you hear the start "gong" when pressing the power button?
    Does the screen go on and show you the gray background? If so, does it show you the Apple logo, or maybe a folder with a question mark?

    If it's an Intel iMac (aluminium) you can try resetting the SMC:
    - shutdown the iMac
    - unplug the power cord
    - hold the power button for (at least) 5 seconds, then release it
    - plugin the power cord and try turning it on

    More theories and troubleshooting when you give me the answers :-)

    • Andrew
      January 16, 2011 at 11:56 am

      Hi Mike
      I hear no gong there is no flicker of light just the sound of a fan ramping up in the distance faintly , then after two seconds a wheezy winding down of I presume the hard drive , it is an Intel iMac bought last Xmas . I will try your suggestion even though I am reluctant to actually switch off now .
      Thank you for responding .

      • Mike
        January 17, 2011 at 5:38 am

        PRAM reset, Safe Boot etc. usually "kick in" after the gong. Unless you have the sound muted or defective speakers your Mac doesn't even get to that point.

        Your description sounds a lot like a faulty RAM.

        If you are confident you can try booting up with only one of the RAM sticks [one by one]. Removing and or changing the RAM is kind of a no-brainer for iMac's as described here http://support.apple.com/kb/HT3918

        If this seems to work I recommend changing both of the RAM sticks even if you can fixate the problem to only one of them.

        Apart from that you are best of visiting an Apple authorized Service Provider near you.