FreeAgent Drive is Read Only on Mac OS X

OK, after having read through these responses and having tried some different things, I wanted to post what worked for me, because there seems to be some confusion here. First of all, I took the route of trying the ntfs-3g driver. I downloaded it and looked at the directions for a Mac. I have only had my Mac for a little over a year and working with Fink or whatever was not user friendly, so I looked elsewhere. It turns out that Mac does INDEED do Fat32. As one of the other sites that I read says, it is not really very clearly done, but if you use the Mac disk utility application (it comes with Mac OS - I am using 10.5), then you can reformat the disk. It says "MS-DOS (FAT)" for creating the partition, but if it is a large partition, then it will automatically use FAT-32. So I have just formatted my 1.5 TB Free Agent drive with that and copied a .DOC and .PDF file onto the drive. It works fine on the Mac. Then I take it over to my Windows Vista machine, plug it in, and Windows Vista recognizes it, opens the Doc file in Word, the PDF in Adobe Acrobat, and it sees all of the disk space on the drive (after formatting, it says it is actually a little over 1.3 GB - Western Digital stretches it a bit by calling it 1.5 GB). Anyway, the bottom line is that it seems to work like a charm. One caveat is that apparently formatting such a disk with Windows Vista is limited to 32 GB partitions (see MS docs here - http://technet.microsoft.com/en-us/library/cc766145.aspx). However, that seems to be arbitrary and set by Microsoft and is not a technical limitation of the FAT32 technology. So that is how it worked for me.

Ok, first, the format is NTFS not NTSF. NTFS is the new windows format that replaces FAT32. And no, mac does not use FAT32, that is a windows format, Macs natively use HFS+. This does not mean you can't use the drives though. Macs can write to NTFS, you just need the right driver. I found it here: http://www.ntfs-3g.org/

The disk drive format between Mac and PC are very different. Mac uses FAT32 and PC is NTSF. Mac can only read NTSF. If you want the Mac to read and write the drive you will need to reformat the drive to MAC standard which is Fat32.

The OP wants it usable on BOTH PC and Mac.

That would be FAT32 since both operation systems can read and write it.

PC can not read Mac OSX Extended Journaled drives (Native to OSX) so that is not an option.

Mac's can't write to but can read NTFS (Native Window NT/XP/...) so you can at least move data in one direction.

You have to create a new partition with the Mac Disk Utility, overwrite the old partition. Start Disk Utility, choose the drive (not the volume!), click options, pick GUID, choose Mac OSX Extended Journaled, enter a name for the volume..click apply and wait a little...done :)