iMac HD and Screen Turns on Randomly

Discussion in 'iMac' started by Hwangman, May 12, 2014.

  1. Hwangman macrumors newbie

    Joined:
    Mar 30, 2012
    #1
    I have a 3 year old iMac (21.5'' display). For the last several months, it will randomly start itself up. I hear the hard drive spinning up, and after about 10 seconds, the monitor turns on.

    I have adjusted the screensaver settings and used the boot disk utilities to diagnose/repair the hard drive and disk permissions. No luck. I can't find a consistent answer to what is going on via Google searching. Any suggestions?
     
  2. simsaladimbamba

    Joined:
    Nov 28, 2010
    Location:
    located
  3. Hwangman thread starter macrumors newbie

    Joined:
    Mar 30, 2012
    #3
    It's sleeping. It's set to go to sleep after about 30 minutes of non-activity, and I also have a mouse gesture set up to turn the monitor off if the cursor is placed in the top-left corner.
     
  4. MartinAppleGuy macrumors 68020

    MartinAppleGuy

    Joined:
    Sep 27, 2013
    #4
    Check the batteries of the mouse. If the mouse is disconnecting, the iMac will switch on.
     
  5. eattherich macrumors 6502

    eattherich

    Joined:
    Jul 8, 2011
    Location:
    Berlin
    #5
    Here's a few things to consider:

    - Do you have any external USB devices connected?
    - Do you have any Bluetooth or Wi-Fi devices connected?
    - Is "Wake for network access" checked in Energy Saver preferences? If so, try unchecking it
    - (As mentioned) Check the batteries of any connected devices
    - If you know what you're looking for then you can note the time it wakes and check the system logs (either in Terminal or in the Console app). Searching "wake reason" narrows it down but, as mentioned, you need to know what you're looking for.

    If it's happening regularly then I'd try different variations of your setup to try and rule out certain things, i.e. no Bluetooth devices, Ethernet as opposed to Wi-Fi, no USB devices while sleeping, etc. I went through a very long AppleCare support case with my previous iMac and I tried lots of things. In this case it ended up being a hardware issue but most of the time it's some software, network activity, or a connected device. As my case went on I was eventually asked to format the HD and reinstall OS X completely (not a restore, an actual fresh install). This is supposedly a common fix as I guess it just ensures that any user (or third-party software) settings are nuked. I hope you figure it out.
     
  6. Hwangman thread starter macrumors newbie

    Joined:
    Mar 30, 2012
    #6
    Wow, thank you for the very detailed response.

    My mouse and keyboard are wired, so I know it's not either of those. The iMac is hard-wired for internet, so it's not the wi-fi either. Most of the USB ports are in use, though only 1 has anything actually attached (external hard drive, which is powered off when the iMac wakes up).

    I'll check the settings you mentioned and, as a last resort, may reinstall OS X. I've been meaning to upgrade lately anyway, so if I'm unable to find the culprit, maybe it's a good excuse to update to one of the newer versions.
     
  7. eattherich macrumors 6502

    eattherich

    Joined:
    Jul 8, 2011
    Location:
    Berlin
    #7
    You're welcome. Yep, it's definitely worth running the latest OS that your system is supported by, which in your case (3 year old iMac) is the latest - OS X 10.9.2. I totally feel your frustration with this issue so if I think of anything else that I was asked to try by AppleCare I'll add another comment. Out of interest, how often would you say it wakes up by itself? Is there any kind of pattern to it? I always use a Bluetooth keyboard and mouse and one time the advisor asked me to try a night with a wired keyboard and mouse. I submitted some logs the day after and then all I heard for a week was "yep, it's that mouse that's waking it up". I told them a hundred times that I only tried it once but it took them a while to let go of that. Regardless, my point is that they seemed very confident that it could have been a wired mouse waking it up. As I've always used wireless I can't say how easy it is to wake the iMac with a wired mouse but if there's a pattern you recognise then I guess there's no harm trying a different keyboard and mouse if you have others lying around. Once I'd tried most of the basic settings that the advisor suggested it got a bit deeper - permissions changes, etc. That's what eventually led to a fresh install. It also might be worth setting up a new user account and letting it sleep while logged into that. At least then it could rule out any third-party software you have running on your user account. Good luck.
     
  8. Hwangman thread starter macrumors newbie

    Joined:
    Mar 30, 2012
    #8
    I've been thinking of an upgrade for some time since I'm still on 10.6.8. There are some programs I use that require at least 10.7, so maybe I'll make the jump soon and see if that happens to resolve the "waking" problem.

    Since I've been paying attention to the problem, it seems to wake up 1-2 times per day.

    The iMac originally came w/a wireless mouse and keyboard, and I experienced the same behavior. I have one other wired mouse I can try. Outside of that, I'll check those basic settings you mentioned and then look at upgrading the OS.
     

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