Model A1419 / Late 2012 / 2.9 & 3.2 GHz Core i5 or 3.4 GHz Core i7 Processor, ID iMac13,2

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How to recover my data

I have fallen victim of this same type of failure on this same type of machine. My 27" imac from late 2012, emc 2546 has the 3TB fusion drive configuration, which is under a recall since last june 2015.

I had no idea that drive could be a potential problem and didn't know there was a recall.

When the drive failed, it did it progressively and silently, and I only noticed at some point that my time machine backups were not completing all the way.

I have an alternate backup external drive that I connect only once in a while for an additional backup besides the main one, so when I started having issues with the backups not finishing, I tried having both backup drives online and alternating between both to attempt to get full backup again and on both backup drives. Since the backups were rather large and would not complete all the way, I excluded some data to reduce the size of the sets, which did work, at first, so I was working my way back to full backup.

I was unlucky and the drive continued failing further and I could not get any good backup, ran out of free space on both external drives, which caused time machine to delete older copies to make room for the new ones that never fully succeeded. When the drive finally failed enough so nothing would work and I could no longer start the machine up from anything, I was left with a non functional mac and an incomplete backup on both backup drives.

That missing data is the most important part for me, as the rest that is backed up is mostly system files and applications, which I can easily replace.

When I found out about the recall, I took my machine to the only local apple store available and they confirmed my machine and its configuration to indeed be covered under the recall.

However my data must be recovered and they could not do it successfully.

All they offered was to simply forget all about my data and get my machine fixed for free under the recall, which is unacceptable, or to ship out my drive to an external 3rd party data recovery company, which is outrageously expensive, and at the same time the recall would no longer apply and I would be invoiced for the imac repair on top of the data recovery from that other company.

A small fortune, which would basically pay for a whole new machine of the same type.

I could not do this, so I just got my machine back.

Now I have that seagate drive 3TB, which is one with the apple specific firmware AP15. The electronics on that drive is faulty and prevents accessing the data and even interferes with starting up the machine from any other drive.

I see many such drives on ebay, but none have the apple specific firmware.

What are the chances of getting a pcb from an other such drive without the apple firmware to actually work properly on this failed apple modified drive?

What interests me above all, is to get the failed drive to work again, so I can get my data back. If then I have to find some other way to get a proper drive back in the machine, so be it. At least I would get my data.

Can anyone point at some useful info about this please?

Update (11/19/2015)


I'm assuming the issue is with the pcb because this was the cause mentioned by the various technicians at the store that handled the issue. And I also found that when the drive was failing, it was also preventing any other way to startup this machine, from any usb drive, flash or not, and even from the external super drive with an osx install dvd. I would think if the machine is prevented from starting properly from anything other than the failed internal drive, this would also point to something having gone badly wrong with the electronics on the failed drive, perhaps causing issues on the controller.

I have no absolute certainty of course.

And as far as backup is concerned, I did have a proper time machine backup going, one permanently on the machine, plus an other that I connected once in a while and that I also tried connecting at that time while the drive went bad. The failure of the drive happened slowly, silently and progressively. It screwed up a good part of my dual backups, and the most part of what's missing is actually my most precious data. The part that are still on the backups are the least necessary ones, such as the system files, applications, etc... but my needed data is the most part missing. I'm sure a small portion is likely recoverable from the backups, but going after the deleted files, but since the failing backups have rewritten data so many times and cause so many deletions, I don't think enough can be recovered from there.

I am trying to get an other identical drive and attempt a swap of the pcbs. If this works properly and IF the only thing that is truly wrong is on the pcb, then this should solve the problem. However if you're right and something else is wrong with the micro-mechanical stuff inside, obviously this will fail as well and the disk set will need to be the part to be swapped out from the failed drive and put in an other fully functional one.

I know this is supposed to be done in a clean room by skilled techs, but I think the costs are quite high and I can't afford this much.

I am left with a very bad situation and precious data held up in there. I need to find a workable solution.

One thing that I am wondering is if I get an identical drive with the standard seagate firmware instead of the modified apple firmware, is this going to function properly?

In the case that I attempted a swap of the disks inside the drives, not in a clean room, I don't see what this could do for the short term, just the time to do the data recovery, the dust could not really cause any real issues in such a short time...

Update (11/23/2015)

Here is some reflexion that I'm having about this situation. I believe it's important, and actually vital to properly understand how the fusion drive works and how it's setup, to have any chance of recovering any data.

Everything I've read about the fusion drive until now pointed to the fact that fusion is NOT a caching scheme, where data/files are not duplicated and shadowed on the SDD from the HDD. So the SDD is not used as a separate volume shadowing a part of the HDD.

So here are some very important points that I must be certain about, before proceeding with further tinkering:

1) fusion drive isn't a caching scheme: data isn't duplicated and shadowed.

2) fusion drive is basically a RAID JBOD arrangement, with extra software logic to move files between the SDD and HDD according to how fast we need them to load up, by having the most often used files moved to the SDD

3) the fusion drive resulting volume is an aggregate of the space from both the SDD and the HDD, so the total space is that from the SDD PLUS the HDD

4) the data is spanned across the 2 parts of the fusion drive, not duplicated

5) separating the SDD from the HDD would break the fusion drive and render any data on either useless

Now I'm really not certain that having the HDD removed from the system and the SDD kept in there would be a safe thing to do, because I'm afraid something would happen that would cause a write operation on the SDD, essentially causing the fusion drive to break. I know if nothing special is done with the SDD without its associated HDD, logically nothing should be written to it, but how can we be certain of that?

One other thing to consider is the idea of using a kit to make the failed HDD an external drive via usb or whatever. How would osx behave when seeing its previous fusion drive setup being split across controllers that are different from the previous setup? Having the SDD still in place as before and the HDD moved to an external USB location. Would osx try to consider that a fusion drive again?

If the SDD card is removed, then there is no possibility of confusion.

One other possibility, with the SDD card removed, is to have the failed HDD as an external drive with a hardware write blocker on it, making absolutely certain nothing will be changed on it, as the blocker would intercept any write command to the drive and block them. Then perhaps, if there is a way to make the drive work again, a full duplication could be made from that drive, block by block (by dd ?), to a fully functioning drive of same capacity, which would then allow safe access to the data from the good drive, but then how would that duplicate drive be recognized in the fusion drive if we reassemble it later?

Quite a bit to be addressed before doing the actual data recovery.

All this reflexion should hopefully help other in the same situation, I hope.

Update (12/07/2015)

I am still expecting the tools that I was missing to work on this imac, but I have received a replacement drive of the same model. That replacement drive is the same model and it dates from roughly the same period, however it's not an apple specific drive with the apple firmware.

Being of the same type, model and rough period, I assume that other drive would be prone to the same kind of failures, so I won't rely on it for the long term. I only plan to use it to recover the data and then I will look at an other replacement drive, hopefully better and I certainly hope not prone to the same issues.

When I get those missing tools, I will then be able to attempt something, and one thing I will try first, before touching anything on the fusion drive, is to try out that replacement drive to bring up the machine to a functional state, where I can run all kinds of tests on the hardware to make sure nothing was wrong beyond the failed drive.

I have not found any reliable info detailing exactly how those faulty drives actually fail. This would be important info to make decisions on the proper methods to use for data recovery, and what to avoid to not have any other problems.

There is also no official source of detailed info about how exactly the fusion drive works. Conflicting info can be found, but overall the consensus about the fusion drive functions is more like what I described earlier on this thread, and that fusion drive is not a shadowing/caching scheme, so the HDD cannot be separated from the SDD and data is not duplicated.

This obviates using the pair of devices together at all times and never at any time try to use them one at a time.

There are issues that I am wondering about though:

1) when using a non apple drive, they are basically identical hardware wise, and although the firmware differs some, electronically it seems to me that they should be the same. So why do we need an extra temperature sensor on the non apple drives? As this would likely be built-in the pcbs and perhaps it's a matter of firmware to relay the sensor's info to the system... Or are there further differences between the apple and non apple drives? would the apple specific drive have extra hardware on the pcbs, along with the different firmware, to read and send the temperature info to the system?

2) if a failed drive has been imaged to a non apple drive, of the same type, but without the apple firmware. Does the fusion drive scheme read anything beyond what's on the drive platters to recognize the HDD to match it with its original SDD? I mean would anything outside of the data recorded on the drive be read to fully identify the drive as being part of the fusion drive to pair it with the SDD? That is drive serial number and such info...

In a case of data recovery that was done by imaging the failed drive to an other of the same type, model and capacity, can the duplicate copy be used as is with the SDD to get back the fusion drive, even though the actual drive is not the original one?

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From your added comments I don't think you have a drive problem at all (drive PCB or the Drive Can). This sounds like your main system logic board is having problems. Before you do anything bring your system into an Apple Store as this type of failure should be covered under warranty.


My machine was at the local apple store, for a good 3 weeks, leaving me without it a long time.

They had removed the failed drive (set, SDD+HDD), tried to do the recovery, unsuccessfully, and then they shipped this drive set, without the machine, to their better equipped colleagues at an other bigger regional store, so they could attempt the recovery there. They also were unsuccessful and just shipped the drive set back to the local store. They have not tried anything else besides using the drive as it is now. That drive is obviously failed.

That machine is a late 2012 and it's out of warranty, and only the drive was covered by the recall, so since I could not get them to get my data back, I just got my machine back, opened, as is, with the failure still there.


I've got nearly the exact same problem. I didn't even take my machine to the Apple store for fear they'd wipe any data that I need to recover. I'm about ready to send my drives out for data recovery, but very very interested in your approach Didier, and I really hope you are successful!


I don't know how this will turn out, but the data recovery companies are sharks and I can't afford what they try to charge, so I have to figure this out on my own.

I finally received my new drive, the one that I plan to use for the long term, as I don't plan to use that other one which is of the exact same model as the failed one. I specifically avoided getting one more of the same to hopefully avoid the same issue come back and bite me later.

So my new drive is the 4TB, also seagate, but this one shouldn't be prone to the same issue.

I'll be working on putting this drive in the machine in the next couple of days, and I will remove the SDD first, basically put the whole fusion drive aside, out of the machine, for safe keeping.

I must be sure the machine has no other problems, and I plan to do some file scavenging first on the messed up backup, because I think the most precious data that was deleted to make room for more failed backups may still be salvageable from there.


If I do need to recover data from that failed drive, since I can't afford paying big bucks to those sharks, I will have no choice but to attempt the recovery myself.

After all the exchanges with the various technicians and recovery company specialists, I know that the faulty part is definitely the head assembly, and I do have an exact same model working drive to work with, so the plan would be to swap out the head assembly.

Obviously this does mean opening that "sealed" case and work on the micro-mechanical parts. I don't need to take the spindles out, just swap the heads.

The recovery companies normally would make a clone from that, but I don't need the whole thing, and with the head assembly swapped, the drive may start working again, long enough to finish the backups that wouldn't finish before.


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You are assuming the issue is within the PCB of the drive. Sadly, the mechanical drive mechanism is the more likely failure here.

Not much you can do here once the drive is gone. We & Apple strongly recommend backing up your data on an external drive so so you can recover your stuff. I realized this is too late here. If you really need whats on the drive then you'll need to send it out to the recovery service to try to salvage the data.

Sorry for the bad news ;-{

Update (11/19/2015)

While it is possible to swap out the hard drives PCB it is not something I recommend. First. You'll need to find the EXACT same drive as yours. You won't need a clean room just to replace the exposed PCB. You will need a special cable adapter: OWC In-line Digital Thermal Sensor for Hard Drive Upgrade for 27" iMacs 2012 and Later. For the replacement HD.

What ever you do Don't open the metal case of the drive! There is nothing in side that you can fix without very special tools and a clean room environment.

I still would not recommend opening your system unless you have the correct tools as it's quite easy to damage the the display assembly. The newer 'Thin Series' iMacs are much harder to open than the older models.

Update (11/20/2015)

For now don't worry about your current drive we need to get your system back up first. See if you can get the replacement drive due you, just hold it on the side. If they don't give it to you I suspect they are not so sure it's the HD here but something else.

OK, Do you have access to an external drive (USB or Thunderbolt) it can be just a USB thumb drive? If so, You'll need to prep it off a working Mac system. The goal here is to make it a bootable drive. I would recommend copying over to it the OS installer as you'll likely need it later.

Now with your external drive, open your system and remove the HD or at least disconnect the cables. Follow this IFIXIT guide: iMac Intel 27" EMC 2546 Hard Drive Replacement. Now carefully put the display back on and plug in your bootable drive. Now restart your system pressing on the Tab key so you get the boot manager select your external drive and let the system start up (USB will take a while). Can you get that far? If so you'll need to replace just the HD with a new unit (you'll want to use a second new drive here). As this new drive won't be an Apple custom HD you'll need to order the sensor kit from OWC I've pointed to you to.

If you can't get that far the issue is not your HD but the system logic board or the SSD unit. You'll now need to open the system up again and this time you'll need to pull the SSD and retest Again follow this IFIXIT guide: iMac Intel 27" EMC 2546 SSD Replacement. If the system still is unable to boot up with now just your test drive the logic board needs replacing.

As for your important HD, you'll need to get a SATA to USB adapter cable kit: Universal Drive Adapter so you can access the drive externally. If you have a friend with a Mac you should be able to gain access to your drive from the other system to salvage your important data if the drive is still good.

Universal Drive Adapter Image


Universal Drive Adapter


iMac Intel 27" EMC 2546 Blade SSD Image


iMac Intel 27" EMC 2546 Blade SSD Replacement



2 - 3 hours

iMac Intel 27" EMC 2546 Hard Drive Replacement Image


iMac Intel 27" EMC 2546 Hard Drive Replacement



1 hour

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If I can't swap the pcbs, I don't see what else could be done to recover the stranded data.

I can get another identical drive, and make sure the pcbs have the same model number and rev, although it looks unlikely that I will be able to get that with the same firmware.

I don't think I have any other choice, but to try swapping the pcbs. I have not planned to open the rest of the drive, unless I'm sure the problem is inside and the pcb swap doesn't help getting at the data.

The thing is, that drive has failed, obviously and all I care about at this point is to get my data back, so even if I was to open the case and it would not be done in a clean room, it wouldn't matter, as the time needed to recover the data isn't very long and nothing can happen from any dust from a non clean room during such a short period, then the drive would not be reliable afterwards anyway, so the eventual contaminants that could make their way in the case would not matter.

I just can't afford giving $100s to some data recovery outfit.


When I was desperately trying to recover my data before I knew about the recall on those machines, it got to a point where it would no longer boot from anything at all, not an external drive, not from a usb bootable thumb drive and not even from an osx install dvd. This made me think something was wrong with the main sata controller, or that the failed electronics on the failed drive was causing a malfunction on the sata controller.

I have my machine back and before I try anything on the failed drive's pcb, I will pull out the ssd to keep it safe with the failed hdd outside the mac, and I will try to put an other drive in there to see if I can get it up and running again. At some point before it failed completely, I had managed to run hardware tests and nothing was shown wrong anywhere.


I think you are over fixated on your data on your HD to see the bigger picture here. Start with getting the system up using a new drive, get the system up first. Don't use the replacement drive you are owed we'll use it to salvage the data on your bad drive if that is the issue. I'm still thinking you have a different problem here. If you can get the system up and running with a fresh drive you can then move onto salvaging your data on the bad drive. But we'll first try a few salvage techniques before replacing the drives PCB.


That drive was a fusion drive, so if I was to put an adapter and try to access data on another machine without having its sdd also there, obviously there is no way this could work, and if the slightest write operation was to be done on that drive, the risk is very high to really lose data.

I think removing the fusion drive set for safe keeping is a must, while I can put an other drive in the machine to make sure it all works properly. Then I can think about data recovery...


The recall was a head parking issue within the sealed drive can which again you can't fix. There is nothing you can fix inside the drive can (platter & heads) without being in a clean room and very special tools.


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I had a company just fix my little flood issue/ water damage from a broken pipe a few weeks ago causing my Mac to go haywire and had similar issues. I found it to be my system logic board so had to pull the SSD and fix then reboot it. At first it didn't reboot so thought my logic board would have to be replaced but then after the third attempt it booted. Maybe some residual condensation.

I backed up my HD however immediate with a SATA to USB adapter cable kit then connected a co-workers Mac to gain access to my drive (Horray!) from the water logged system to salvage my files. Long story short, it seems my computer dried out and everything seems to work but I was able to successfully boot up and back up!

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So this wasn't related to the seagate 3TB drive issue. But if that's the type of drive in that machine, it may do this again later, this time caused by the faulty drive.


Hi, reading this thread 2 years down the line as I am in the exact same situation now. Same 3TB Fusion Late 2012 iMac. HDD is out and have managed to pull some data off using a PC program. Alas, all my photos RAW and JPEG were unretrievable, or haven’t copied over. Only thumbprints and few JPEGS copies over. Not bothered about other data, just photos which are precious memories. Dilemma now is to either reformat or replace HDD with the hope that I can maybe get to these files at a later date. Haven’t taken SDD out as yet. What was your outcome didier?


@thomasmilton - I don't think Didier ever got his data off his drive. I suspect he did the worse thing here. He was thinking he could fix the head assembly within the sealed disk chamber. Please don't do that!

Sorry to say I've dealt with this problem too many times and the only hope you have here is sending out your drive to a good recovery firm. They have the needed skills and tools.

Let me put it bluntly, I'm not a brain surgeon and I'm sure you're not one either. All we would do is kill the patient.

As far as your blade SSD, there is little hope it would have anything useful. The SSD holds copies of the files accessed frequently which would be the OS & Apps. It might have the very document you had open when the system was shut down.

I won't reuse the HDD drive! Don't format it if you still want to try to save your pictures. If the drive is still readable you might want to try a Mac based recovery program as it might have better success. I would recommend this one: Data Rescue 5


I couldn't afford to send the drive out to those VERY excessively expensive (sharks) data recovery people. They just pray on people who really need their data and take advantage of the situation. In an "ideal" world, of course the swapping of internal parts in a drive would have to be done in a "clean room", but in practice, since the drive only needs to run for a short while to grab data and then that drive can be discarded, if done clean enough, there is no real need for any clean room.

And those "special tools" used by the data recovery people, are mostly data recovery software, and they have to be careful when handling the "head" transplant, because of the very strong magnet that makes it quite hard to put the heads back into place properly.

There is no easy way to get anything back from the SSD by itself, and if it is paired again with a different drive, it will be wiped during formatting, so all is surely lost along the way there, and the SSD doesn't contain all the data anyway...




In my misfortune, I ended up somewhat fairly lucky, because with my dual time machine backup, plus the extra periodic time machine backup that I only connect every few weeks, despite the screw ups from the failed backups when the machine was malfunctioning, I was able to recover most of my stuff by myself, working around the corruption and useless failed backups. So in the end, I didn't shell out all that cash (that I don't have), not to data recovery people, not to an apple center, not anyone, except when I bought a new replacement drive from ebay, which was a !&&* of a lot cheaper than what the apple center wanted for it.

Apple has become a true shark and even though Jobs was pretty bad with his concept of making everything as closed as possible and un-repairable by users, Cook has gotten much worse and the real innovation has dropped a lot.


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didier godefroy will be eternally grateful.
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