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220 Views 9 Replies Latest reply: Jan 20, 2013 7:49 AM by Mike Osborn RSS
jonno098 Calculating status...
Currently Being Moderated
Jan 19, 2013 2:39 AM

imac 20" 2.4ghz 320hd

model number :A1224

I decided to do a reinstall on my imac

I formated the hard drive ( don't know why )

now when I put my OSX disc in and hold down the C key ,

it says OSX can not be installed ???

I'm lost no idea how to reinstall ,



  • Matt Clifton Level 7 Level 7 (26,940 points)
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    Jan 19, 2013 4:32 AM (in response to jonno098)

    You may have incorrectly formatted the drive. When you reboot from the installer, before you go through the steps, use the Utilities menu to find Disk Utility. There, try the reformat again, but make sure you choose "Mac Extended format" for the file format. Use the Advanced button and make sure the partition scheme is GUID.


    Then continue through the installation (no need to reboot inbetween). Does that help?



  • rkaufmann87 Level 8 Level 8 (40,600 points)
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    Jan 19, 2013 7:33 AM (in response to jonno098)

    You need to re-format the HD. Because we have no idea what version of OS X is installed it's a little tough to tell you how to do it. However you will need to launch Disk Utility, then click the Partition tab and select GUID. Then click the Format tab and format as Mac OS Extended (Journaled) and you should be able to install OS X. If you still have trouble take the machine to your local Apple Store (along with OS X) and then can help you out. If you don't have an Apple Store close by then visit and AASP.

  • Mike Osborn Level 4 Level 4 (1,205 points)
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    Jan 19, 2013 8:36 AM (in response to jonno098)

    What is printed on the disk you're trying to install?  (Leopard, Snow Leopard, etc.)  Did this disk come with the computer?

  • Mike Osborn Level 4 Level 4 (1,205 points)
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    Jan 19, 2013 9:25 AM (in response to jonno098)



    It sounds to me as if you're not booting from the CD for some reason. Booting from the CD is pretty slow, since it has to read the optical disk and transfer it into memory before you can do anything with it.  If memory serves, when I booted from the CD on my old iMac, I had to hold the C key down for a minute or more before I was assured it was booting from the CD and not the internal drive.


    If you're able to boot from the CD, and follow the advice already provided here (from the menu bar at the top, choose Utilities, then Disk Utility, you should be able to reformat your drive. Then just choose Install OSX by double clicking the icon showing in a window on your desktop and reinstall Leopard.

  • Shootist007 Level 6 Level 6 (16,640 points)
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    Jan 20, 2013 5:04 AM (in response to jonno098)

    Did you FIRST Format the hard drive as Mac Extended (Journaled) with a partition table of GUID?


    If you have then maybe you are using a disc from an Older Mac then you have and that version of OS X is not compatible with the present hardware in the newer Mac.


    Please state the year the Mac was made and or when you bought it. If it was sometime in 2011 then it more then likely came with Lion Pre-Installed and certainly that disc will not work.

  • Mike Osborn Level 4 Level 4 (1,205 points)
    Currently Being Moderated
    Jan 20, 2013 7:49 AM (in response to jonno098)

    I tend to agree with Shootist's opinion that you're trying to install a mis-matched version of OSX on your Mac. (Assuming you've formatted the hard drive as per advice provided earlier in this thread).


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