iMac won't boot, please help.

Discussion in 'macOS' started by jamie.hunt, Jan 24, 2010.

  1. jamie.hunt macrumors newbie

    Joined:
    Oct 9, 2009
    #1
    Hey guys, hopefully someone will be able to help me out here.


    I have an intel iMac running Snow Leopard. I have not been able to get it to boot for the last 3 days.

    When I turn it on it gets to the white screen with the grey apple logo and stays there for ages, sometimes 10 minutes. If it does get past this I only get a blue/grey blank screen. Nothing else.

    Interestingly enough I can access my files on it from another mac on the same network when it is at the Blue/Grey screen stage.

    I have unplugged everything except the keyboard and mouse.

    I have tried booting in safe mode by holding the shift key whilst it boots. When I do this on the white screen with the grey apple I then get a progress bar show up, It doesn't fill though and the iMac then turns its self off again.

    Has anyone got any ideas on whats the problem and how I can fix this?

    I would be very grateful

    Thanks!
     
  2. miles01110 macrumors Core

    miles01110

    Joined:
    Jul 24, 2006
    Location:
    The Ivory Tower (I'm not coming down)
    #2
    Can you boot from your restore disc? Insert it and hold "C" on startup.
     
  3. jamie.hunt thread starter macrumors newbie

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    Oct 9, 2009
    #3
    I dont have a restore disk to hand... Will my snow leopard upgrade disk work?
     
  4. spinnerlys Guest

    spinnerlys

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    #4
    Yes, it will work.
     
  5. jamie.hunt thread starter macrumors newbie

    Joined:
    Oct 9, 2009
    #5
    Ok, found my restore disk.

    Tried holding down C with both snow leopard upgrade disk and restore disk, Cant get past white screen with grey apple.

    If I am holding down C the progress bar does not show.

    Ah I left it just loading and when I went back downstairs It asked me for which language I wanted to install Mac OS X. I have clicked on English and It now wants to start the instillation.

    What do I do next? I Don't want to wipe anything, i just want to fix the OS i've got.
     
  6. spinnerlys Guest

    spinnerlys

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    #6
    It sometimes can take up to five minutes to boot from the DVD, so wait that long. The progress circle should appear though, but that can take a while too.
    If you hear your Superdrive spinning and accessing the DVD, then it should be fine.


    You can also press and hold the Option/Alt key after the startup sound chimes and see the bootable devices connected to your Mac, which at least should include the DVD and, depending on the damage to the internal HDD, it should also show the Mac OS X HDD boot volume.

    Do you have another Mac with Firewire and a Firewire cable?


    [​IMG]

    Go to the Menu Bar, select Utilities > Disk Utility and select your HDD in there and hit the Verify Disk and Verify Permissions button to see what kind of error messages you get.

    If one of those give you errors you can click the Repair Permissions or Repair Disk button.
     
  7. jamie.hunt thread starter macrumors newbie

    Joined:
    Oct 9, 2009
    #7
    Both verify and repair could not be completed because of an error.

    It says:
    invalid node structure
    invalid record count
    invalid key length
    Volume check failed

    The underlying task reported failure on exit.



    I do have another mac and a firewire cable.
     
  8. spinnerlys Guest

    spinnerlys

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    #8
    I guess the partition table might be screwed, but there are tools for that.
    Have a look around this forum with MRoogle (my sig) and see if you can find anything about that, as I never had to do that, but read about it a while ago.

    If that doesn't work, you can use Data Rescue 3 (99USD) to recover the data on your iMac's HDD.

    For all those things mentioned you need to connect both Macs via Firewire and start the iMac in Target Disk Mode (search for it if you wanna know more about this) by starting the iMac and holding down the "T" key until the Firewire logo appears, it looks like a "Y".
    That enables you to mount the iMac's HDD as an external HDD on your other Mac, but since it may be broken, you need to use some tools to access the data, tools I mentioned in the first two paragraphs.
     
  9. jamie.hunt thread starter macrumors newbie

    Joined:
    Oct 9, 2009
    #9
    Thanks very much for your help...

    Say the information on the hard drive isn't valuable.

    Is it easier to do a clean install of the OS on the iMac and is it easy to do this?
     
  10. spinnerlys Guest

    spinnerlys

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    #10
    Yes. You can use Disk Utility to erase your HDD and it will write a new partition table doing so. As Format (file system) you select Mac OS Extended (Journaled).

    There are plenty of more thorough guides out there though if you need more information.
     
  11. jamie.hunt thread starter macrumors newbie

    Joined:
    Oct 9, 2009
    #11
    Thanks for your help.

    In disk utility it says that the disk "MacintoshHD" isnt mounded. When I have gone to try to reinstall Mac OS X it asks me where I would like Mac OS X to be installed and there is no HD to select.

    How can I fix this?

    I would be grateful for anyones help. Thanks
     
  12. spinnerlys Guest

    spinnerlys

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    #12
    Open Disk Utility, select name of HDD (something like ST3250.... or so) > Macintosh HD, go to the Erase tab and select Mac OS X Extended (Journaled as Format and hit the Erase button, or is everything grayed out?

    After that you can select a HDD to install to, not before.
     

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