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I have an external hard drive with a bootable HFS+ partition on it. I have unallocated space on this drive that I want to create a new exFAT partition on, so that my entire family's computers, both Macs and PCs, can use the new partition. I still want to be able to boot into the HFS+ partition from a Mac. I can only find sparse and/or conflicting information on this. On the one hand, I am reading about people not being able to access the exFAT partition from a PC unless the partition is actually created using Disk Management on a PC. On the other hand, when I try this on a Win7 system, I get a warning saying that the operation I selected will convert the basic disk to a dynamic disk, and I won't be able to start installed operating systems from any volume on the disk.

How can I create an exFAT partition on my external disk that is readable by both WinXP (SP3), Win7 and Mac, without losing the ability to boot from the existing HFS+ partition?

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UPDATE: I think the issue may be the partitioning scheme. I know that it must be GUID partition table in order to be able to boot the HFS+ volumes, but I don't know what Windows 7 can and cannot handle. – Phil M Apr 14 '12 at 3:03
up vote 2 down vote accepted

XP? Sorry, but you can't get there from here. Intel based Macs boot from GPT partitioned hard drives, and Windows XP can't read GPT discs at all without a third party driver, if one exists.

If you create the partition on your Mac, Vista and 7 should see it, I would think, unless Apple is doing something wrong with the partition table.

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Wikipedia mentions that the 64-bit version of XP understands GPT, on the off change the questioner is actually running that. – Kyle Jones Apr 14 '12 at 1:04
Very few people ran XP-64, and anyone that did should know that it's different enough to mention explicitly. – afrazier Apr 14 '12 at 1:15
You're right about XP not reading GUID partition table disks. BTW, I'm mostly using Win7 & Macs, but one machine is WinXP. But what about Win7? Does the partitioning scheme need to be MBR for Win7 to cope, or can it handle GPT disks? – Phil M Apr 14 '12 at 3:01
According to the Microsoft GPT FAQ, yes. – afrazier Apr 14 '12 at 12:57

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