Need to reformat to install Mountain Lion?

Discussion in 'iMac' started by edtorious, Jul 25, 2012.

  1. edtorious macrumors 65816


    Aug 14, 2007
    San Diego, California
    I have an iMac and I'm trying to upgrade to Mountain Lion but I encountered a problem, I'm about to install Mountain Lion but it says it cannot install because my HDD is not a Mac OS Extended (Journaled) format. I went to disk utility and checked my startup partition and it shows Mac OS Extended only. How can I change it to Mac OS Extended (Journaled)? I'm hoping to change it without deleting the contents of my HDD, I'm just really hoping to do an upgrade and not do a clean install. Any help or suggestions will be greatly appreciated. Please advise. Thank you.
  2. hfg macrumors 68040


    Dec 1, 2006
    Cedar Rapids, IA. USA
    Well ... one way would be to do a Time Machine backup on the existing HD installation, then re-partition as OS X Journaled. Start the recovery installation of OS X and when prompted select "restore from Time Machine backup"

    This will have the added advantage of giving you a full backup of your system, and you can continue doing incremental backups so you don't lose your data.

    I think you might even be able to "Option Key" select the Time Machine backup on boot and simply restore your existing system, then upgrade normally to Mountain Lion.

    There are other ways using cloning software such as Carbon Copy Cloner to create an image on a external disk, then boot from it and partition your original disk, and finally clone the external disk back to the original. However, I think this method is more complicated and less useful if you intend to continue to use Time Machine for future incremental backups.

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