How do I install ML on an external drive?

Discussion in 'OS X Mountain Lion (10.8)' started by Spaceboy88, Feb 17, 2012.

  1. macrumors member

    Apr 2, 2005
    I just downloaded my version of Mountain Lion from the App Store, but am wondering how I can install it on a separate hard drive as I don't want to overwrite my primary OS. Anyone know how I do this?

    Thank you
  2. macrumors member

    Oct 12, 2011
    Strange. Seeing as it isn't on the App Store yet :rolleyes:

    Got it from a torrent?
  3. thread starter macrumors member

    Apr 2, 2005
    No, it IS in the App Store if you have an Appleseed Beta Tester download code, which I have.
  4. macrumors regular

    Apr 4, 2008

    I did the same thing yesterday (instead of an external, i just partition a piece of my HD to run ML in. Installed and expanded, ML is about 10 - 11 GB. I partitioned 40GB so I can have some room to play and test).

    But all you have to do is once you have your partition made (or external loaded onto your mac). Run the installer, it will ask where you want to install it. (just don't point to your main HD).

    After the install, you can reboot your computer, and hold the option key and you will see your various OS instances and you choose the one you want.

    Simple actually.
  5. thread starter macrumors member

    Apr 2, 2005
    Excellent! Thanks.
  6. macrumors 6502a


    Nov 9, 2009
    How do I get the apple seed download code so I can download ML from the app store so I can do the same install it from my external drive?
  7. macrumors 603


    Feb 3, 2010
    United Kingdom
    What do you guys recommend for the ML partition? I was going to try it with in Parallels or like this, I was thinking 20GB. I don't want to download any apps, just play around with the OS.

    Plus, is it easy to delete the partition once ML is actually out?


    You need to be a part of Apple's OS X Developer programme ($99 p/a)

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