Problems with partitioning

Discussion in 'MacBook Pro' started by eravulgaris, Jun 13, 2013.

  1. eravulgaris macrumors newbie

    Jun 13, 2013
    Hi guys, I've got a (big?) problem. I wanted to format my entire harddisk (128GB SSD, probably doesn't matter) to install Mountain Lion on it. There was a bootcamp partition on it as well, which I erased. I did this in Disk Utility in recovery mode (when I pressed CMD + R in the beginning).


    The problem is, I wanted to erase my whole HD so I could have it whole again, but I couldn't because it said something about: "unable to unmount partition".

    So now I'm left with a BOOTCAMP partition and a greyed out part that I can't use. I've tried resizing the HD to take the gray part, but it doesn't work.

    I've got no idea what to do...

    Thanks in advance guys. These problems are hard to explain.
  2. pnyc macrumors 6502

    May 12, 2007
    Brooklyn, NY
    Since you want to format the entire drive simply make a bootable Mountain Lion USB key, boot from it, run the Disk Utility from within the installer, delete all partitions and format the resulting space as one OSX partition, proceed to install Mountain Lion.
  3. eravulgaris thread starter macrumors newbie

    Jun 13, 2013
    Will this make a difference? Because I did run the Disk Utility from within the installer (CMD + R brings it to the screen with Disk Utility and options to reinstall your OSX)
  4. Yahooligan macrumors 6502a


    Aug 7, 2011
    It will make a difference because cmd-R boots off of the internal drive, which you're attempting to reformat/repartition. You can't do that when you're actively using it, so you need to boot off of a device that you're not wanting to wipe and start fresh.

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