Reintsall OS X 10.8. Mountain Lion without Recovery Partition

Discussion in 'OS X Mountain Lion (10.8)' started by amad3us, Sep 14, 2012.

  1. amad3us macrumors newbie

    Sep 14, 2012
    Hi community,

    First of all,
    I am an idiot. I have absolutely no idea what I was thinking
    when I deleted the recovery partition.
    I was installing Windows via Bootcamp and had my Mac booted off a Windows 7 installation HD. Because there was an error when trying to install windows on the partition created by bootcamp i 'played' around and ended up having deleted ALL partitions. Now I am only running Windows 7 on my mac... (what a shame).

    What can I do to reinstall Mountain Lion? Do I have to go to an Apple Store to get help? I can't believe how stupid that was.
    I work with the new MacBook Pro with Retina. And I do own Apple's external disc drive and a Mac Pro if that helps anything.

    Your help is very much appreciated. Thanks!

  2. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    Not to worry. Just do a command-r (hold both keys at once) when you boot and you will be taken to Internet Recovery. This is built into the firmware (EFI) of your rMBP. It will see you have no Recovery HD or OS and automatically download the OS from Apples servers.

    Once you get to the install screen, look in the Utilities menu and start Disk Utility and format the entire drive as Mac OS X Extended. Then proceed with the OS install. It will take a while because the entire 4.7GB install has to DL from Apple.

    Once the OS is installed use the Migration Assistant to import your data from your backup.

    Did your machine come from Apple with Lion or Mountain Lion? If it came with Lion, what I described is going to reinstall Lion then you will have to go to the App Store in Lion to redownload and install Mountain Lion.

    If your machine came with Mountain Lion, what I described will install Mountain Lion.

    Alternatively, if you machine came with Lion and you don't want to have to DL the OS twice, you can use your Mac Pro to download ML from the App Store then make a USB key installer on the Mac Pro and use it on the rMBP.

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