# creating FAT32 partition on external hdd on mac osx



## mpdst11 (Oct 5, 2008)

I am trying to reformat a 500 GB USB HDD to one FAT32 partition so that I can use it on a Mac and a PC.  I have seen many references to using the disk utitilty and creating a partition in MS-DOS format, but my computer does not have that option.  The only four options I have are Mac OS Extended, Mac OS Extended (Journaled), Unix and Free Partition.  Am I missing something here?


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## VirtualTracy (Oct 5, 2008)

Hello mpdst11 & welcome to macosx 

What model Mac and OS version do you have?


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## nixgeek (Oct 5, 2008)

Be aware that FAT32 only supports a maximum volume size of 32 GB and a file cannot exceed 4 GB in size.

http://support.microsoft.com/kb/314463

You'll either have to format the 500 GB drive as NTFS and use NTFS-3G and MacFUSE, format the drive as Mac OS Extended, or create multiple 32 GB partitions in FAT32.


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## ElDiabloConCaca (Oct 5, 2008)

FAT32 can be formatted larger than 32GB and Windows will recognize a FAT32-formatted partition larger than 32GB -- it's just that Windows XP's disk management utility will not let you format a FAT32 volume larger than 32GB (go figure!).

It's possible that you've selected an incompatible partition map format for the drive.  A FAT32 volume needs to have the "MS-DOS" (or something similar to that -- I don't have the means to verify at the moment) partition scheme in order to function properly.  When you select your hard drive (not the indented volume below the hard drive) in the left-hand sidebar and select the "Partition" pane, click the "Options..." button below the graphic of the partition scheme and ensure that the correct partition map scheme is selected.


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## nixgeek (Oct 5, 2008)

ElDiabloConCaca said:


> FAT32 can be formatted larger than 32GB and Windows will recognize a FAT32-formatted partition larger than 32GB -- it's just that Windows XP's disk management utility will not let you format a FAT32 volume larger than 32GB (go figure!).



Interesting.  So formatting a volume as FAT32 in either GNU/Linux or Mac OS X will bypass that limitation?  I wasn't aware of this.  What about Windows Vista?

EDIT: Here's more information to further confirm EDCC's post:
http://forums.macrumors.com/showthread.php?t=240804

I have thus been schooled.


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## ElDiabloConCaca (Oct 5, 2008)

It's a no-go for _creating_ FAT32 volumes greater than 32GB in size on Vista, too, but there are tools to help you get around that limitation:

http://padraic2112.wordpress.com/2007/04/05/windows-vista-fat1632-support/

The general consensus is that if you want a FAT32-formatting volume larger than 32GB, use a Linux distro or Mac OS X.  Quite simply, use anything other than Windows (ironically, the operating system FAT32 is meant to be used with).


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## mpdst11 (Oct 6, 2008)

The mac I am using is a 3.5 year old ibook, mac osx version 10.3.9.

I am aware of the file transfer size limitations of the FAT format.  It will not be used for any large files, but rather a lot of smaller files.

To be more specific about my predicament, I currently have a desktop PC and a Mac laptop, but my version of Windows XP has crashed an I am using a Linux boot disk to try and recover the files from the PC internal hard drive.  However, I am having trouble getting the Linux OS to recognize my external HDD.

I have been informed that if I reformat the drive into a single FAT partition, I will be able to write to it from the Linux OS on my PC, and I have done the research to figure out how to use my Mac laptop to do this, but I don't seem to have that option.

When I am in Disk Utility, Erase tab, I have the option to erase the disk with an MS-DOS File System Volume Format, which I have done.  This makes the external HDD readable on the Linux PC.  However, it is not writable.

On the partition tab, I do not have the choice to create an MS-DOS or FAT partition, nor do I have an options button below the graphic of the partition scheme.  If anyone has any suggestions on what I can do, I would greatly appreciate it.  Thanks.


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## wakester (Oct 18, 2008)

Hi, you probably already figured out how to do this but I thought I'd reply in case others have searched and ended up here.

I'm using 10.4.11.

In Disk Utility, since I only needed 1 partition for my whole external drive, I just used Erase.

I clicked on the name of the disk (in my case it is 465.8 GB Seagate).
Change the format to MS-DOS File System.
Then clicked Erase.

It works just fine for backing up all my files.

When I plug it into my Windows XP machine and right click on the disk and go to Properties it shows the format as FAT32.  Cool.

Roger


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## mpdst11 (Oct 18, 2008)

thanks wakester,

this is what I ended up doing as well.  for some reason the external hard drive was still unwritable when my pc was booted using knoppix (linux), but i booted using a bart pe boot disk and i was able to get it going.


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