Partitioning Help for an External Hard Drive

Discussion in 'Mac Basics and Help' started by Deadmanwade, Jul 20, 2009.

  1. Deadmanwade, Jul 20, 2009
    Last edited: Sep 13, 2012
  2. LTX macrumors regular


    Dec 25, 2008
    Vancouver, BC, Canada
    Before doing any partitioning work, it's always a good idea to back up your data! It's also good to make sure you've made the right selections before you hit Apply! :)

    Plug in the drive, turn it on, and open up Disk Utility. Select the drive on the left side (if it's indented, it's a partition, and you don't want to select that) and click the Partition tab on the right side.


    I'm going to assume that the drive already has a partition on it. If so, follow method 1.

    Method 1: Click the + sign under the partition diagram to add as many partitions as you want.
    Method 2: Under "Volume Scheme", use the listbox to choose how many partitions you want.

    Use the handles on the bottom right of each rectangle to resize the partitions, or enter a size on the right side, and hit Apply when you're ready. All the data on the drive may be erased!

    When that's done, choose each partition in turn on the left side, go to the Erase tab, and give the partition a name and file system. For your Time Machine partition, that should be HFS+ Journaled. If you want to let Windows computers put data on the drive, make a partition use NTFS.
  3. -tWv- macrumors 68000


    May 11, 2009
    You may need to change the partition scheme from MBR (master boot record) to GUID. I had to do this when first partitioning and setting up my external hard drive that was initially formatted as FAT. This post will teach you how to do this.
  4. Deadmanwade, Jul 20, 2009
    Last edited: Sep 13, 2012

    Deadmanwade thread starter macrumors newbie

    Jul 20, 2009
  5. OutSpoken macrumors 6502a

    Jun 9, 2009
    Once an External HDD is partitioned or reformatted, is it non-reversable:confused:

    Reason I ask is, I have just reformatted my external drive from FAT32 to NTFS to allow copying of a file that was greater than 4gb.

    But once i've copied the file off, I would like to reformat back to that possible?
  6. LouisBlack macrumors 6502

    Jun 21, 2007
    Balham, London
    Nah, you can do it as many times as you like. Just use disk utility to erase the drive using HFS+.

    To the OP. It isn't really important to partition the drive unless you are worried about people on your network being able to see your Time Machine back ups. The Time Machine folder can live happily with other files on the drive. In this way you don't have to predict how large you will want each partition to be.

    The advantage of partitioning would be being able to set access restrictions to the Time Machine partition.

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