Resolved How to do a Clean install of Mountain Lion on Mountain Lion

Discussion in 'OS X' started by phr33k, Nov 25, 2012.

  1. phr33k, Nov 25, 2012
    Last edited: Nov 25, 2012

    macrumors newbie

    Joined:
    Nov 22, 2012
    #1
    Hi guys,

    This may seem like a dumb question, but I have been searching for ages and can't get what I need. I used cmd-r and reinstalled OSX 10.8 from there, but i didn't realise it wasn't a clean install. All my apps and files are still there.

    My Air cam with Mountain Lion preinstalled, so how to I download it to do a totally clean install without paying for it in the mac app store as I don't fancy paying for it again? Or it it possible to do a clean install from the cmd-r?

    I really appreciate and help.

    David
     
  2. macrumors G5

    Macman45

    Joined:
    Jul 29, 2011
    Location:
    Somewhere Back In The Long Ago
    #2
    Follow these steps:

    First you need to create a bootable install copy of ML using :
    http://www.cultofmac.com/180518/sin...on-diskmaker-gets-os-x-mountain-lion-support/

    You need a USB stick of 8GB Minimum.

    There are two ways to perform the install. One is destructive ( all files and data will be erased) To do it that way, boot your Mac whilst holding "OPTION" then enter Disk Utility and format your HDD. Reboot whilst holding OPTION again with the USB stick connected and choose "EFI Boot" then install from there .

    The non destructive method is the same, just skip the format hdd step. Boot holding OPTION and choose EFI boot. This method will not remove your files and apps.
     
  3. thread starter macrumors newbie

    Joined:
    Nov 22, 2012
    #3
    Thanks for your reply. Can I just ask you, where will I get the install file from?
     
  4. macrumors G5

    Macman45

    Joined:
    Jul 29, 2011
    Location:
    Somewhere Back In The Long Ago
    #4
    1) Download a copy of ML and put it on your hdd

    2) Run the app in the link i post, it will find the copy of ML and create the bootable USB stick for you ( stick needs to be connected)

    Once created, follow the steps I posted to re-install.
     
  5. thread starter macrumors newbie

    Joined:
    Nov 22, 2012
    #5
    Ok Thanks. Where will I get a copy of mountain lion? My air came with it reinstalled, so it says "buy" in the mac app store? is there anyway to get it?
     
  6. Moderator

    OllyW

    Staff Member

    Joined:
    Oct 11, 2005
    Location:
    The Black Country, England
    #6
    If you bought a brand new Mac with Mountain Lion pre-installed you should be able to download it again from the MAS. Contact Apple and they should be able to sort it out.
     
  7. thread starter macrumors newbie

    Joined:
    Nov 22, 2012
    #7
    Ok i will. I was justa bit wary of clicking "buy", and being charged for it and I already have it
     
  8. macrumors P6

    Weaselboy

    Joined:
    Jan 23, 2005
    #8
    If your Mac came with ML, you did not buy it from the App store so it won't show up there. If you click "buy" you are going to get charged for it.

    You can just do a command-r boot to recovery and erase Macintosh HD then install ML. That will be a completely clean install and it will DL Mountain Lion from Apple's servers for the install. You do not need to get it from the App Store. While in recovery, Apple's servers will recognize your machine's serial number was sold with ML and just give it to you.
     
  9. thread starter macrumors newbie

    Joined:
    Nov 22, 2012
    #9
    Thanks weasel boy! followed as per instructions and it work great! thanks again!
     
  10. macrumors member

    Joined:
    Mar 28, 2011
    #10
    Usb

    Hi, i want to do the same but don't have an 8GIG USB stick, can i whop it onto my external HDD?
     
  11. macrumors P6

    Weaselboy

    Joined:
    Jan 23, 2005
    #11
    Yes. Just make a 8GB partition and point this app to the partition when it asks where you want to put the installer.
     
  12. macrumors member

    Joined:
    Mar 28, 2011
    #12
    Is it fairly easy to partition an external HDD?
     
  13. macrumors P6

    Weaselboy

    Joined:
    Jan 23, 2005
    #13
    Yes, very easy. This article shows how to partition a drive. The article is for an internal drive, but it works the same for an external.
     

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