How To Partition An External Hard Drive For PC Usage [Mac]

Joshua Lockhart 19-09-2011

partition external hard driveI recently picked up an external hard drive for my Mac (one terabyte of memory to be exact), but I really needed to use it for both my Mac and my Windows laptop. However, as you may know, Mac formatting and PC formatting for external hard drives are totally different.


Granted, it’s possible you may already know how to partition an external hard drive 4 Things You Need To Know When Buying A New Hard Drive Read More DIY-style. Furthermore, your hard drive may already come with onboard software that does it for you (but honestly, I really don’t like using those included apps at all). However, let’s take a look at how to do so.

Open The Disk Utility Application

In order to prep things for your partition, it would be best to use an external hard drive that you absolutely do not have any important files on whatsoever. If you already have thrown some stuff in there (like I did when I was first trying this out), go ahead and copy them over to your computer. With that being said, make sure that the external hard drive is at least plugged in for this to work (the reason I say this is the same reason that costume companies write “cape does not enable wearer to fly” on their superhero outfits).

In case you have never used this app before, just go into your Mac’s Applications, click on the Utilities folder, and find the Disk Utility application. (For those of you still searching, it looks like a hard drive with a stethoscope on it.) Open it up, and you’ll be treated to a brand-spankin’ new window on your screen.

partition external hard drive

partition external hard drive pc


On the left-side of this window, you will see the different hard drives connected to your computer. You will see your main hard drive (or hard drives) located within the computer on this section of the window, but you should also be able to find your external hard drive somewhere in the midst of it all.

partition external hard drive pc

After you do this, be sure to open the contextual menu of this hard drive (two-finger click on trackpad or CTRL + click) and select the Unmount option of the drive. This is very important in order for this project to work for you.

Set Up The Partition

As you might be able to tell by the screenshots, I have already partitioned my external hard drive (JxHart Mac and JxHart PC). However, you can still follow along by looking at the rest of the Disk Utility window.


When you first look at this window, you will see a few tabs that give you a variety of options for your external hard drive. One of them will simply say Partition, and as you might be able to guess, this is the one that you want to select. After doing so, you will arrive on a menu that provides you with what you need to partition the hard drive. The item on this page that you should look for will be a drop-down menu labeled Volume Scheme.

partition external hard drive pc

Since we are partitioning the external hard drive for just both Mac and PC, you should set the Volume Scheme up for two partitions. Once you do this, you will be given two easy-to-use graphic images of simple boxes that represent the two partitions. What you can now do with these is set up how much memory you want for each partition.

Work Out The Sizes And Formats

On my external hard drive, I gave the Mac portion 950 gigs of space and the PC portion 50 gigabytes of space simply because I use the Mac side a little bit more. With that in mind, I am still able to open up the PC portion of the hard drive on my Mac and take files from it. However, I cannot add or delete files. That’s why it’s good to have the partition.


After you have decided on the sizes of each partition, you should then go back and change the names for each one. I would suggest that they reflect what you will be using each partition for, such as “Mac HD” and “PC HD”. Realistically, you could change the names of the partitions before sizing them, but this is really up to you.

partition external hard drive

Finally, you absolutely need to change the writing format of your external hard drive for each partition so this does exactly what you are wanting this to. To do so, select the Mac OS Extended (Journaled) option for the Mac side of your external hard drive and the ExFAT How to Format a Large Hard Drive With FAT or FAT32 The FAT and FAT32 formats support up to 16TB. Yet Windows sets a 32GB limit for formatting with FAT or FAT32. We'll show you how to format larger drives. Read More option for the PC side of your external hard drive.

When you are ready for the partitioning to begin, simply click  Apply and you are good to go. It’s really simple to do, and you should be able to complete the project within minutes.



Most likely you can  (definitely) follow a similar process with other operating systems such as Linux or even some hipster OS that we’ve never even heard about. Furthermore, you could make two or more Mac-related partitons as a way to just keep yourself organized. I’ll also assume that you could use one of those partitions for Time Machine 4 Resources to Become a Backup Master with Time Machine [Mac] Read More if you are using something a little more permanent.

Which other apps or programs do you use to partition hard drives or external hard drives? Do you have any other tips to add on to what I have written here?

Related topics: Computer Maintenance, Disk Partition, Hard Drive.

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  1. Martin
    November 30, 2011 at 5:35 pm

    Thanks J, incredibly useful.  I have partitioned my hard drive and now have two icons on my screen, one which Time Machine is currently updating and another I have named Windows 7.  My new PC laptop arrives today.  Are there any other steps I will need to take for the laptop to recognize the partition on the hard drive?

    • J. Lockhart
      December 1, 2011 at 6:42 am

      Hm. Well, Martin... As far as I know, you should be able to plug and go. I set up a Mac and a PC side for my own external hard drive, and after plugging up, the PC recognized it right away.

  2. Yaisha
    November 28, 2011 at 9:01 am

    This is all well and good, but how do I select the exfat option, it does not appear in the drop down menu?

    • J. Lockhart
      December 2, 2011 at 1:34 pm

      That's incredibly odd, Yaisha. I really don't even know, for it should be there. Perhaps you could post to MakeUseOf Answers to see if anyone else is dealing with this issue. It works fine for me, and I really don't know how else to explain it. 

      In the mean time, I'll be searching myself to see if there are any solutions. I'll make sure to follow up if I find anything.

  3. royalpurple
    November 1, 2011 at 10:44 am

    Hi is it possible to make 3 partitions: 2 partitions for Mac (with 1 partition for time machine and the other 1 for just storing files) and 1 partition for Windows. Will I still use the MAC  OS extended (journaled) format for the 2 mac-related partitions or can I use ExFAT on all 3 partitions? Im looking for a way to organize files in 1 external hard drive. At the same time, I want to make use of the  time machine.  Would I be able to open the files stored in the MAC partition on another laptop such as windows? sorry I have the slightest idea when it comes to these things. thanks a bunch! 

  4. Chetan Sachdev
    September 23, 2011 at 12:39 pm

    I m running Snowleapord 10.6.8, but I don't see option to format "NTFS for Mac". I don't want to create two separate partitions rather enable RWX permission in both Windows and Mac. How I can achieve that ?

    • Deepred2129
      October 19, 2011 at 12:12 am

      You can't. Mac doesn't support making a partition of NTFS (Windows) However you can partition it to FAT to use on both windows and MAC (but NOT time machine backups). Or you can partition half of it for Mac & half as NTFS through: 1) Partition half of it as MAc journaled Then the other half as FAT. The connect it to your Windows PC and format the FAT32 partition to NTFS.

  5. Chris
    September 20, 2011 at 8:54 am

    If I may humbly add: As my main computer is a Windows 7 PC and my laptop is a Mac, I find that using "NTFS for Mac" really solves all my problems, plus gives me permission not only to read NTFS on my Mac (you can do that anyways without 3rd party software) but to write/delete on any NTFS volume with no problems at all.

  6. Srv
    September 20, 2011 at 5:39 am

    I have a Problem.
    i have Three drives in my laptop.
    and windows 7 Ultimate is installed.
    Yesterday wen i tried to Make my system dual boot nd tried to install Windows 8,it said It cannot be installed on any other drive except C:.
    Wat can I do.Please help

    • J. Lockhart
      September 20, 2011 at 5:45 am

      This is a little beyond me and this article, Srv. Have you tried MakeUseOf answers?

  7. Farah Haddad
    September 20, 2011 at 3:40 am

    Hi, I have a 1TB external HD and 500 GB Internal HD on my MBP. Can I partition the 1TB HD so that I use part of it for Time machine backup and the rest to store files on it? If yes, then what is the minimum partition size for the time machine part to work properly, is it 500GB??
    What I am trying to do is to use the 1TB as a time machine drive and iTunes, hence, I will just connect one external HD and have all what I want in it.

  8. Mike
    September 20, 2011 at 2:57 am

    Worth to mention is that: 
    For Apple computers with Intel processor Disk Utility will use the GUID Partition Table by default which is only supported by Windows XP 64bit, Vista or later. If you are running Windows XP 32bit you might not be able to access the disk. 

    Older Macs with a PowerPC processor (prior 2006) use the Apple Partition Map which is not supported by any Windows version. 

    You will always want to take a look at the bottom of Disk Utility which Partition Map Scheme is used for the currently selected (external) drive. For backwards compatibility you may want to hit the Options button and select Master Boot Record.

  9. Matt Rigby
    September 20, 2011 at 1:40 am

    This is a good guide for older versions of Mac OS X...

    EXFAT for both Mac OS X & Windows:

    Both Mac OS X 10.6.5 onwards & Windows 7 now support read/write EXFAT, I'm sure you could use EXFAT for the entire disk.

    Of course, you may struggle if you wish to use it on Linux-based or older OSes, but I believe standard Linux support for EXFAT is on its way.

    [ But, if you need a partition for Time Machine, it would be easier to have a HFS partition. ]

    NTFS for Windows, Linux & Mac OS X (with NTFS-3G):

    And if you use NTFS-3G for Mac, you can use NTFS for 3-way R/W support for Windows, Linux & Mac OS X.

    I've been using both NTSF-3G & EXFAT with Mac OS X for a while now, and they work great.

    Can anybody see a problem with this that I've missed?

    • J. Lockhart
      September 20, 2011 at 2:40 am

      Hey Matt!

      I actually used this method for Snow Leopard (so your suggestions are relevant), but it simply worked for me. That's why I wrote it.

      However as for your input... you really can't argue with what works, right? So if it works for you, then it probably would work for me, and heck, it will likely work for everyone else that reads this article! Many ways of doing similar things, I guess.

      By the way, I stayed away from any Linux info with this article seeing that I have zero experience with it. (Granted, that could always change.)

      Thanks for the info!