How to RE-install OSX 10.8 as a fresh install?

Discussion in 'OS X Mountain Lion (10.8)' started by erkanasu, Aug 27, 2012.

  1. erkanasu macrumors 6502

    Jan 11, 2006
    I already installed 10.8 using the standard procedure (download from mac app store). aka NOT a fresh install.

    How do I reinstall 10.8 as a fresh install? Create a bootable USB drive? Or can I use the partition it created the first time?

  2. Herbfeng macrumors newbie

    Aug 27, 2012
    u can download 10.8 iso and use udisk to reinstall
  3. heisenberg123 macrumors 603


    Oct 31, 2010
    Hamilton, Ontario
    it will be in your purchased tab in the Mac app store download again but this times once its downloaded to run it just quit it if it auto opens.

    than use this small app and a 8GB usb stick to make a bootable copy of ML

    now once the usb is done, plug it in and restart your mac holding the option key when you hear the chime you will see the usb to boot from, now you can use disk utility to do a clean install
  4. Eddyala macrumors newbie

    Jul 11, 2012
    I live in the greatest city in the world-N.Y.C.
    Hello All,I would also like to know about the clean install? Do you need to use a USB or what? I already have a USB with ML already on it, so could I use it on my iMac and hold the option key after I hear the chimes? I would like to know so I can try it too. If you know, Please let me know...Thank You.:apple:
  5. Macman45 macrumors G5


    Jul 29, 2011
    Somewhere Back In The Long Ago
    Step By Step

    You will need a USB stick of OVER 4GB ( I used an 8 GB stick for my copy)

    Download ML from your purchased tab but cancel the installation when prompted.


    Insert the USB stick and start the creator application.

    When complete (it takes a while with USB 2) You can eject the USB stick and you now have a bootable image,

    Start your MAc whilst holding down the "Option" key

    If you wish to, you can erase the drive to start afresh, or perform an (EFI) over the top installation of ML

    Over the top will retain all your Apps, a clean install will require you to download and re-install them from the App store. If you have third party apps, make a note of them prior to the Installation
  6. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    This post contains a good PDF at the bottom with a step by step.

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