Last night, a friend asked my to give him a copy of a word document. He handed me an external hard drive and left.

I plugged the hard drive into my file server running Windows Server 2003, opened disk management and clicked OK. (I know that in Windows 2003 you need to manually assign a drive letter to external drives.)

I then looked at the drive in disk management and it said that it was unallocated space. I called my friend and he said that there was data on the drive, but he used it with his Mac Book.

Aperantly when I clicked OK in disk management I converted the from HFS+ file system to something else.

Is there any way to undo the disk convert? I immediately removed the drive, so there was no writing to it. Windows did not format the drive, it just converted it. Is the data still there? All the data recovery programs I have are for windows, can they read the Mac file system?

I need to get the data back, what can I do?

  • Did you read what it said before you clicked OK? Or you just blindly clicked on it? Maybe it said "I need to erase your entire drive, would you like to continue?"
    – davr
    Commented Mar 19, 2010 at 20:16

4 Answers 4


Well, if it says it's unallocated space, that means you just blew a new partition table onto it. He might be able to re-partition the disk in his MacBook with the correct partition sizes and locations and get the data back.


More then likely, it did not convert the drive at all.

When he takes it and plugs it back into his system, it will probably be just fine, it's just that your PC can not read the MAC formated drive.


Grab knoppix and boot a PC with the disk attached, with that done you can use parted and the rescue command do rescue 0 999999 where 999999 is the size of the disk.

Here are the docs http://www.gnu.org/software/parted/manual/html_mono/parted.html#SEC24


If it was Mac formatted you may be able to recover the partition table with DiskWarrior.


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