Comments on: Restore an Apple Partition Map

By: Broes

Broes — Mon, 23 Jan 2012 16:07:19 +0000

@”A. Guy”: I know the feeling when you first discover drive corruption. However, conquering that corruption by manually re-adding each and every partition totally eradicates that first feeling. Congrats on the (partial) recovery!

By: A. Guy

A. Guy — Mon, 23 Jan 2012 15:34:26 +0000

Thanks a million, bro. January 2012 and you saved my ass. Four years after the fact!

I used TestDisk first, to get the proper starting & length values of my lost APM partition (they were slightly different than pdisk’s, BTW). Then with your step-by-step pdisk guide, I got my entire 2TB partition back.

I had another APM 1TB disk that Win7 cannibalized, but even though TestDisk found the HFS partition underneath the NTFS, when I ran pdisk I guess too many files had been overwritten. The resulting “rescued” partition and files were basically scraps of larger files, i.e., useless. So I lost about 250GB there, but fortunately, most of those were apps that I can reinstall or had already backed up.

By: chrisall

chrisall — Mon, 07 Nov 2011 12:49:41 +0000

Hi, this article is still very relevant. I purchased a non-booting imac g5 & have used testdisk from a ubuntu 10.04 live CD to check the partitions. It looks fine except for invalid signature on block0. I used dd to copy the first 5 blocks to a file on a USB stick and using ghex can see I have the same problem as the op that the APM at block 0 has been overwritten.

I now need to manually edit block 0 and dd it back to the drive. Fingers crossed!

By: ThaRealKapone

ThaRealKapone — Sat, 05 Nov 2011 11:14:55 +0000

YOU SAVED ME MAN!!!!!!!! I went from being illiterate with stuff like this two weeks ago and now with your help I was able to save my external myself instead of havin to take it into a shop! Not only that but people before you told me to jus give up on trying to restore the file paths and just salvage the files but the issue I had with that was that I saved all my Garageband session folders on this hard drive and to salvage them would mean that I’d lose the organization of the folders in such a way that I’d prolly never be able to put them back together again. Thanks again!

By: Broes

Broes — Wed, 02 Nov 2011 13:28:55 +0000

@Andre: happy this article is still relevant!

By: Andre

Andre — Tue, 01 Nov 2011 11:30:17 +0000

Thx Dude!
You saved my Studioworks of 8 month =)
Damn, i really have to make my backups on occassion.
Thank you very much!

By: Jason

Jason — Tue, 26 Apr 2011 17:31:58 +0000

I’ve a similar problem to this, but I don’t know if it’s similar enough for these instructions to work:
I had an APM drive with an HFSJ that I resized to make room for a Linux install.
Decided to delete the Linux partition because I wasn’t going to use it.
Somehow this deletes the HFSJ as well.

I used TestDisk to find the data I needed to feed pdisk to restore the HFSJ. It gave me error messages. Looking again at what TestDisk gave me, I believe that the reason deleting the Linux partitions got rid of my HFS was because they overlapped. The last sector of the HFS looked to be exactly the same as the first one of the Linux — as far as I know, this is a Bad Thing.

Long story short, trying to get the partition recovered I ended up writing a new blank partition where the one I was trying to recover went.

Good news: All still HFSJ, still APM.
Bad news: I can’t seem to find any way to force this to restore with the old data.

I could, theoretically, buy some data recovery software or use recphoto to get back any unfragmented files — with recognised metadata — in a big lump with no file names, but I neither have enough free space anywhere to put them all, nor do I want to deal with hundreds of gigs of unsorted unnamed files.

I can find loads of references to: Yes it should be possible to just reconstruct the lost partition table. Not a single piece of advice how that doesn’t involve sending my drive to a data recovery pro for over $1000 and letting him rebuild the partition table through a combination of hex-editors and voodoo.

AM I screwed or can some twist on this process work? I’ve tried Stellar Pheonix, but it didn’t seem to be very effective — it’d get half way through scanning the drive then crash. Does it, perhaps, require a machine with better than 512M of RAM despite not saying that anywhere?

By: Psycho

Psycho — Thu, 03 Mar 2011 04:24:43 +0000

Actually when I partitioning my external disk, I don’t remember what partition table I used. Probably I set to default that mean GUID. How I could check my partition table.
So …. is there no possibility if I used this on GUID it will work even though it will change into APM after using pdisk?

By: Petter

Petter — Wed, 24 Nov 2010 22:28:21 +0000

Thanks a lot for this guide. I used TestDisk to get the figures, and then pdisk to edit, initialize, create and write the partitions. Worked splendidly!

By: Dan

Dan — Sat, 05 Jun 2010 03:46:10 +0000

Problem solved, drive restored, thanks to this blog.