How to write a new partition table to save an intel mac HFS

How to use TestDisk to recover lost partition
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Posts: 1
Joined: 31 May 2012, 19:47

How to write a new partition table to save an intel mac HFS

#1 Post by Jillsan »

I have one of the newer macbook pros and I have an external 500gb hard drive. I only used a portion of the hard drive as hfs.

While I was on a windows computer, I stupidly tried to add an ntfs partition to the unallocated space using EaseUS partition manager. An error occured.

Now, when I plug the external hard drive into the mac, I see the HFS partition as "unallocated space."

I attempted to use OSX's Disk Utility First Aid, but this did not work. I used Disk Utility to rewrite the ntfs section as FAT32. This was successful, but the HFS partition was still shown as unallocated space. I have now removed the fat32 partition using Disk Utility and am left with the EFI system partition at the beginning and the unallocated space afterward.

Anyway, I stumbled across TestDisk on the internet, I ran it on the external hard drive and got the following results:

EFI SYstem 40 409639 409680 [EFI]
MAC HFS 409640 408183895 407774256
MS DATA 908183896 943490016 35306121 [NO NAME]

I think this means that I can write the partition table and get the HFS recognized when I plug into the mac.


There seems to be a lot of different guidance about how to write this partition table. Some sites say pdisk, some say fdisk and some suggest ptedit. Testdisk itself (6.14) offers to write the partition table for me.

I am very new to this sort of poking around and am nervous about writing the partition table incorrectly. Could anyone provide me with step to step instructions to recover the HFS partition (which does have data on it). I am very interested in keeping it intact and this seems like it should be much easier! TestDisk was the only software that seemed to do what I had in mind.