Sharing disks between Mac OS X and Windows

I wrote a couple of months back about the Toshiba PX1223E-1G32 320GB external hard disk that I bought (and which I’ve been very pleased with). Well, nowadays the aluminium case makes it a perfect companion for my Mac Mini and my Fujitsu-Siemens S20-1W widescreen monitor.

The trouble is that, in common with most external hard disks, the drive comes pre-formatted for the NT file system (NTFS), used by all modern versions of Windows. NTFS is a great file system – but it is also Windows-specific, at least from a read/write perspective (Linux and MacOS X systems can only read NTFS-formatted partitions). So, to use the disk with a Mac requires a reformat – either using one of the Macintosh file systems, such as HFS+/MacOS Extended (Journalled), the Unix file system (UFS – but not ext3), or FAT32 (MS-DOS file system). Of these choices, only FAT32 is universally accepted by Windows, Mac OS X and Linux systems but it does have some pretty serious limitations, as I soon found.

Firstly, although FAT32 supports file systems up to 2TB in size, the format utilities within Windows support a maximum partition size of 32GB; however by formatting the drive using another operating system or third-party tools, this limit can be overcome and Windows is able to read or write larger volumes. Secondly, and more significantly, FAT32 only supports files up to 4GB in size. That doesn’t sound like an issue until you start copying .ISO DVD images and digital video files around. Pretty soon it became apparent that FAT32 was not the answer.

The solution was using a software product called Mediafour MacDrive, which I found from the Wikipedia article on HFS+ and which has turned out to be really useful. Ironically, I didn’t need to use a licensed version to transfer my data from a PC to the Mac, as Mediafour make a trial version available for download which is valid for 5 days after installation. Having used that as my demonstration of how useful this software is, I decided to buy a copy (proving that users will buy genuinely good software, even if they can get by for free) – at $49.95 it’s reasonably priced (especially with the current dollar exchange rate and as Mediafour offered me a 24% discount if I purchased within 24 hours of requesting the trial version) and when I finally get around to dual-booting Windows on my Mac it will be invaluable. Sadly, the current version of MacDrive doesn’t work on Windows Vista, so I will need to upgrade one day in the future, but for now it’s a great way to share files between Windows and Mac OS X.

10 thoughts on “Sharing disks between Mac OS X and Windows

  1. Hi Mark, thankyou for your blog-entry. It helps me to initialize my new toshiba usb-harddrive for using with my iBookG4.


  2. Hi Mark,

    Thank you for the blog entry and suggestion of using MacDrive.

    Background. I’m a PC user running WinXP taking a video class where all class computers are running Mac OS X. The instructor told the class to buy an external hard drive. The 400 GT Seagate arrived with FAT32 and its intrinsic 4 GB ceiling.

    Should the Seagate be reformatted by the Mac OS, then I should purchase MacDrive, install it on my PC in order to write the Final Cut Pro created avi files (from Mac) to enable me to then read into Premier Elements (to WinXP)?

    And conversely, will I be able to write to the Seagate from the PC avi files that can be read by the Mac using MacDrive installed on only the PC?

    Thanks for any reply.


  3. Hi Kelly,
    If I understand your question correctly you want to reformat the external hard drive on the Mac (as HFS+), then install MacDrive on a Windows XP PC with the aim of being able to read and write to the external drive using either the PC or the Mac.

    That’s should work just fine – I’m pretty sure that’s what I did to avoid the 4GB limit that you are currently hitting with FAT32.

    Cheers, Mark

  4. Hello Mark,

    Good site keep up the good work, I wonder if you could help me with the following.

    I have a few avi files that are > 4 gb on the mac. Now i want to view them on a pc. How should i do that? I already bought a external harddrive en installed macdrive on the pc. but stil no view.

    Can u tell me what to do?

    Thanks in advance

  5. Hi Hans,
    Glad you found the site useful.

    RE: your files that are >4GB – is the external hard drive formatted with HFS+ (the Mac file system)? Assuming that it is, then you should be able to see the files on Windows through MacDrive. If it came pre-formatted then it’s probably either NTFS (in which case you wouldn’t be able to write to it from the Mac) or FAT32 (in which case you would have problems with large files). Otherwise, all I can suggest is raising a support request with Mediafour – they were pretty quick at coming back to me when I had issues with MacDrive on Windows Vista.


  6. Is there any VOLUME-limit working with NTFS-usb-volumes on Mac OS? I have trouble getting a 2TB USB drive with NTFS-formatting to work properly on Mac OS, most of the files have broken headers but the same files work fine on Windows…!

  7. Hi Erik,
    The maximum size of a volume (partition) under NTFS is 2^64 (18,446,744,073,709,551,616) bytes; however as NTFS is not native to Mac OS X, you may well find that Apple’s implementation restricts the volume size – probably best asking the question at the Apple Discussion Forums.

    HTH, Mark

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