Partition disappeared from external drive. Anybody help?

[Carl Abudephane]

Hello,

This has never happened to me in years of using Macs with external drives.
I have two bare 3.5" drives mounted in a caddy connected to my Mac.

All has been fine for a few months. Yesterday I came back home and the lights on the front of the StarTech caddy were flashing orange.
Subsequently found that there was only one partition showing in my finder sidebar.
The drive had two partitions - one was a half terabyte partition with a clone of my Mac.
The other was a 1.5 TB collection of media stuff. This partition simply wasn't there anymore.

I tried disk utility and it says the drive is fine. But when I click on partition it now shows only 1 partition. The other has seemingly disappeared.

From a bit of reading it seems as though all that stuff is still on the drive, but that the partition map (or something like that) has been corrupted somehow, and now that partition is not able to be seen or accessed.

Beyond that I have so far drawn a blank, other than some incredibly complex Terminal-level directions that I think were to do with re-building the partition map, but to be honest I wasn't so sure what they were for!

At the moment I am running something called Yodot Recovery Software which I found after someone had asked about this exact same problem - so far it is still running but saying it needs 23 hours still to go!

Can anybody help me with this problem? Running Mavericks on a 2009 MacBook Pro.
I would hugely appreciate any help.

 

[Partron22]

Before going into full recovery mode, try out the drive in a different caddy. Those can go bad too.

 

[Carl Abudephane]

Thanks for the response. I'll look into that too; it's a two-bay caddy and I'll try out a few things with it to see if there's any fault there.
The bay the drive was in is now occupied by a new drive to transfer any recovered files to - will monitor it.

Be well.

 

[Fishrrman]

If nothing else seems to be working for you, you can try the procedure I describe below.

Do this at your own risk.

I once had a situation almost identical to yours -- I had a multi-partitioned drive, and one of the partitions suddenly became "un-mountable". All the stuff I really wanted (mp3 files) was on the bad partition.

I tried running data recovery software on it (DataRescue), but because the partition didn't mount and seemed "invisible" to the Mac, DR couldn't "find it".

Here's what I did:
1. I RE-INITIALIZED the ENTIRE drive into a SINGLE Mac partition. Yes, did exactly those two things which one would think would destroy any chances of recovery!
(IMPORTANT NOTE: I -DID NOT- "zero out" when I reinitialized. I only did a "quick initialization". DO NOT do a "secure erase")
2. I then used Data Rescue to scavenge the -entire- drive.
3. DR found the files that had originally been on the "bad" partition, and saved them to a scratch disk.
4. Because they were mp3 files, I discovered that if I created a new boot volume, then used iTunes to create a new library using the recovered files, iTunes could read the "metadata" of most of the files, and I got the file names back as well.

Comments:
The process above works because when you do a simple re-initialization, you replace only the directory on the drive, and leave the actual data (which lies out on the sectors of the drive) untouched.
BUT -- now the drive will "mount" on the desktop and become visible to the Mac and to applications -- even if the directory "looks empty".
AND -- data recovery software can "look around" the empty directory, and "go right to the platters", where the data still lies.
Be aware that one of the side-effects of using data recovery software is that you generally lose all folder hierarchies and many file names. This is "par for the course". In my case, because the files were mp3 files with "metadata", iTunes could scavenge through the metadata and recognize many of the previous song names (In some cases I did have to rename the songs in the finder to match).

If running your data recovery software works on the drive as it is now, GOOD!
But if it doesn't, you could try the process I outlined above.
It worked for me when it seemed all was lost...