Today I ran into a drive after using it back and forth form a Mac to other computers. When I went to Manage Computer on Windows XP and attempted to format a partition, I see that the main partition is
“GPT Protective Partition”

So here’s some directions to delete.

How to delete GPT Protective Partition

In Windows XP Professional, if you cannot access or modify GPT disk, you can convert a GPT disk to MBR by using the clean command in DiskPart, which will remove all data and partition structures from the disk.

1. You might see Drives in GPT status.

2. Go to DOS command line (click on “Start Menu”, then “Run”, type in “cmd” in textbox, and hit “OK”)

* Type in “DiskPart” in command line.
* Type in “list disk” in command line to show all disks in this machine.
* Use “select” to set the focus to the specified partition, for example “select disk 1?.
* Use “clean” command to remove GPT disk from the current in-focus disk by zeroing sectors. (if you do list disk again you will see a * next to disk 1 indicating that it is the selected drive).

3. Go back to Disk Management, you can see the hard drive in question are “unallocated” now. Right click on disk info, choose “Initialize Disk”.

4. Choose all drives HD and initialize them.

Notes/Warning: This command will erase all data on the disk, so please backup your data first.