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I just got a new LaCie external hard drive, and I want to copy my files to it so I can take them back and forth between work and home. At work I have a PC and at home I have a Mac, so I need them to be readable/writtable from both machines.

What format do I need to format them in? NTFS, FAT32, other?

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up vote 1 down vote accepted

You have to decide yourself:

  • You could format the disk as FAT32. That way you can't handle files > 4GB. But it'll work on both systems out of the box and it's fast.
  • You could use NTFS. But you'll have to install ntfs3g to be able to write from the Mac. ntfs3g is somewhat slow (last time i checked, 4 Months ago).
  • there are other options (ext2/3, ...), but they require unstable or not easy-to-use software on one or both machines.

I'd stick with NTFS.

[edit] corrected fat32's size limit (4 instead of 2 GB)

[edit] Since OS X 10.6.5 there's another option: extFAT. It's supported by modern Versions of Windows and OS X. Contra: It's proprietary and not supported on all modern OSes (Linux...) and some not-so-recent Versions of Windows and OS X. Pro: It works quite well on modern mainstream-OSes (i.e. Windows and OS X)

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NTFS isn't "easily writable" on Mac OS. I'd use fat32 if file size is not an issue (though NTFS will pretty much be the only way if it is). – zneak Aug 3 '10 at 17:34
FAT32 can't handle files larger than 4GB, not 2GB. From Wiki: The maximum possible size for a file on a FAT32 volume is 4 GiB minus 1 byte (232−1 bytes). Video applications, large databases, and some other software easily exceed this limit. Larger files require another formatting type such as NTFS. – Hondalex Aug 3 '10 at 21:35
Why not exFAT? xxxxx – Fopedush Dec 17 '12 at 5:12
@Fopedush: It hasn't it wasn't available in OS X up to 10.6.5 (AFAIK), which was released in Nov. 2010. My answer was posted before that date. It's an option. I'll update my answer. – lajuette Mar 20 '13 at 15:44

Surprisingly, newer versions of Windows don't allow you to format larger drives with FAT32, and yet Mac OS X does.

I'd format the drive as FAT32 on Mac OS X, and it will be usable in both operating systems.

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... but only if file size is not (and will never be!) an issue. – lajuette Aug 3 '10 at 20:07

If you're up for a little experiment, I noticed that the Apple Boot Camp drivers for Windows allow reading/writing of HFS+ file systems (thus allowing access to your Mac's data when booted into Windows). I only tested this on a real Boot Camp partition, but you could try installing the drivers on your regular Windows machine (after appropriate backups of course). This would, if successful, allow you to use a file system with a more reasonable file size limit than FAT32, which is just a few gigs.

However, you're probably better off leaving the work computer in pristine condition and messing around with drivers and extensions on your Mac at home.

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That's a good point: Are you allowed to install software on your Windows machine, JAG2007? – lajuette Aug 3 '10 at 20:08
yeah, i can do just about anything to that machine. – Joel Glovier Aug 3 '10 at 20:36

I use ExFAT, because it's compatible with both OS's, supports files bigger than 4GB, and volumes over 2TB (there goes Fat32). plus, Exfat was MADE for external and mobile storage.

Make SURE to format your drive on Windows though, and to eject your disk before removing it, if you don't you WILL have trouble, and may even lose your data, because Apple isn't very good at formatting for Exfat.

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Atleast on Mountain Lion, up to 10.8.2, I haven't had issues with 10.8.3, but I haven't had it long enough to be sure. – MarcusJ Mar 20 '13 at 16:30

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