Installing ML on another partition

Discussion in 'OS X Mountain Lion (10.8)' started by pj-uk, Jul 22, 2012.

  1. macrumors member

    Joined:
    Mar 25, 2011
    Location:
    London
    #1
    I'm getting ready for the release of ML and wondered if it was possible to install ML onto a second partition just in case there are some big issues with ML/software compatibility.

    I currently have around 300Gb free on my primary disk and will create a secondary partition to install ML and copy over all my important documents rather than doing an upgrade or copying everything to an external disk.

    Once I've installed (and happy with the performance!) can I just wipe my Lion partition and join the two partitions back together?

    Does this sound feasible? If SHTF at least I will have OS to fall back on to!
     
  2. macrumors regular

    Joined:
    Jul 24, 2008
    #2
    Yup, this works. In fact, I've done this multiple times and haven't run into any issues.
     
  3. macrumors 6502

    Joined:
    Dec 14, 2010
    Location:
    Portugal
    #3
    I'd like to use this topic (if the owner doesn't mind) to try figuring out why I am getting an error when restoring a ML dmg into a USB stick.

    I formatted it to a GUID partition and when the restoring process of the dmg finalizes I get the following message:


    "Restore Failure

    Could not restore - Invalid argument"


    Any ideas?


    Thanks!
     
  4. macrumors 6502a

    Joined:
    Nov 9, 2010
    #4
    If you type

    diskutil list

    after having installed ML on a second partition, you might discover the following has happend:

    Lion
    Lion Recovery HD
    Mountain Lion
    Mountain Lion Recovery HD

    So, no easy merging possible.
    I would advice performing a clean install after having backed up Lion to a cheap external USB drive.
     
  5. macrumors regular

    Joined:
    Jul 24, 2008
    #5
    I have noticed this as well, but the moment you delete the ML partition (using Disk Utility in Lion), it will also automatically delete the ML Recovery partition with it. Then you can merge the free space you created to the original Lion partition (essentially recovering the free space back).

    But backing up isn't a bad idea; I highly recommend it nonetheless, and it should always be done--it's kind of a given when you're doing a lot of testing.
     
  6. thread starter macrumors member

    Joined:
    Mar 25, 2011
    Location:
    London
    #6
    Everything is already backed up on TM, but want to start afresh! I guess the Lion and Recovery partition will also delete if I stick with ML? ;)
     
  7. macrumors regular

    Joined:
    Jul 24, 2008
    #7
    If you upgrade from Lion to ML, then your Recovery partition will also upgrade to the ML version.
     

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