How Do I Partition Main Hard Drive?

Discussion in 'macOS' started by Jetheat, Feb 14, 2010.

  1. Jetheat macrumors regular

    Mar 13, 2008
    I would like to partition my main hard drive so I can install another operating system on the other one and then use either, whenever I wish.

    I would prefer to do this from my external drive (Time Capsule) but I dont think the Time Capsule allows for partitions.

    In Disk Utility, it shows that I have a 931.5 GB Hitachi Main Disk. Underneath that, indented, it reads Macintosh HD.

    When I click on the Hitachi Disk line, it shows me the partition tab.

    I can figure out how to partition it - which is to simply add and name a partition and click apply.
    But I would like to know if this process will erase any data from my hard drive.
    If it does, then it may not be worth partitioning.

    Does anyone know if I can go ahead and just partition it safely without any worries?

  2. MacDawg macrumors Core


    Mar 20, 2004
    "Between the Hedges"
    You can partition without losing data, but it is always advisable to have a backup before doing any such operation

    What OS are you planning to install?

    If you are installing Windows, you would probably be better off using the Boot Camp Assistant to do your partition

    Woof, Woof - Dawg [​IMG]
  3. Jetheat thread starter macrumors regular

    Mar 13, 2008
    Thanks for that. I'll be installing Snow Leopard.

    Any idea how much space I should allocate to that and how do I boot into that?

  4. Steve-M macrumors regular

    Jun 12, 2009
    If you install snow leopard on the second partition, it will boot by default. You can change this by going to System Preferences > Startup Disk. To select which partition to boot from, depress and hold the option key while booting, then select the partition you want to boot from. For the size of the second partition, it would depend on what you are going to do with it. If your going to add more apps, maybe import your iTunes collection, use it like your main OS, I would say at least 80 to 100 GB.

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