Dead SSD in a 2014 27-inch iMac: What would you do?

I’m curious what others would do in my situation, and even writing this out may help me crystallize my thinking. The 500 GB SSD in my 2014 27-inch Retina iMac just died—Watchman Monitoring reported some disk errors, so I rebooted into Recovery and ran Disk Utility, and it wasn’t able to repair the drive. So I reformatted it and tried to restore from Time Machine, but after it got stuck for hours at 61%, I restarted the iMac, and since then the SSD doesn’t even show up in Disk Utility. I’m assuming it’s an ex-parrot at this point. What to do? Some possibilities:

  • Buy a new 27-inch iMac: Given that my iMac is almost 6 years old, I was thinking about replacing it at the next iMac refresh. Since the last one was 395 days ago, there’s some hope that it might not be too far in the future, although we could be looking at this fall, anyway. I don’t desperately need more CPU power, so I could hold out that long.

  • Buy a new MacBook Air: This is related how? Well, I could get a MacBook Air with 1 TB of storage, which is more than I’d generally get for a laptop, and then use it in Target Disk Mode to boot the iMac until such time as a new iMac was available. Then I’d be able to get a 1 TB iMac and move everything over seamlessly. This would require a Thunderbolt 2 to Thunderbolt 3 adapter, but I don’t see any reason it shouldn’t work. The T2 chip doesn’t seem to prevent Target Disk Mode from what I can tell.

  • Boot from my existing 2012 MacBook Air: This is what I’m doing right now, in fact, and it seems to be working fine. The two computers are connected via Thunderbolt 2. I’m suspicious that rebooting the MacBook Air as itself and back again will cause some level of confusion–there were some things (like all my Brave extensions) which disappeared when I booted the iMac with it in TDM. But so far this seems functional. The only reason it’s not a long-term solution is that my iMac had a 500 GB SSD and the MacBook Air has only 250 GB. The setups are thus similar, but not entirely the same in some potentially awkward ways that I’ll be learning soon enough.

  • Replace the SSD in the iMac: This is probably the cheapest option, but I’ve never opened a 27-inch Retina iMac before (a 2009 27-inch iMac yes, but that uses magnets and clips for the screen, rather than stupid adhesive). Still, it’s probably doable, and OWC has a kit with all the requisite cutters and replacement adhesive. The only problem is that if I screw it up, I’ll be getting a new iMac now.

  • Buy an external SSD and boot from that: This is the easiest thing to do, though a bit more expensive than buying an internal SSD. I’d probably go for a 1 TB SSD, since the 500 GB was getting a little small and I couldn’t fit my Photos library on it already. And it wouldn’t be a terrible thing to have a big external SSD around for utility work afterward. I could even use it for a bootable duplicate.

    The big question with an external SSD is whether it makes sense to get a cheaper USB 3 case, since that’s all my 2014 iMac supports in the USB world, or if it would be better to get a Thunderbolt 3 case for faster performance and connect it via the Thunderbolt 2-to-3 adapter for now. The Thunderbolt 3 cases are a lot more expensive, but USB might be more generally useful in the future. I’m not sure at the moment where the bottlenecks really are with external drives—there are clearly SSDs of radically different speeds (the NVME ones being a lot faster and pricier, for instance).

So, thoughts? What would you do?

I would go to my reputable independent repair shop and ask them to replace the SSD in the iMac with a 1TB drive. More expensive than doing it myself, but I would feel safe that with a model this old, they would be able to either do it or know for certain that they couldn’t do it–I wouldn’t be the first one to have presented them with this problem. (I don’t know that this recommendation works for you–I was lucky to find a good shop here in North Carolina, but it’s all about what’s local to you.)

My concern about buying a new iMac–mine is coming up on being ten years old–is the increasing volume of the rumors about a CPU switch and my strong desire not to buy the last model before an architecture switch. I’ve thought about what I’d do if my machine died, and I’m not excited about any of the possiblities.



Hey, you should do them all, write up your experiences, and write off all the costs as a business expense! Good for you, good for us.


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My son has a 27" retina iMac and, last year, we decided to replace the HDD with an SSD. Mostly I wanted Josh to become more comfortable with maintaining hardware. I bought the new drive kit from OWC.

The repair requires a bit of patience and a good-size working space. Other than that, he had no trouble actually replacing the drive. I elected to handle replacing the adhesive, since he seemed pretty nervous about it and it seemed as though the price of failure would be high. I was meticulous about removing the old adhesive (a pretty tedious job), cleaning the parts with isopropanol, and being careful applying the new adhesive (which came with the OWC kit) to align everything correctly so as not to have to move anything later and potentially damaging the adhesive. Oh, and I made sure the machine would boot before I replaced the screen.

After the replacement, the new drive would usually boot and sometimes run for half an hour or so before crashing. We could never get his system fully restored onto it, and I believe that it soon started getting SMART errors. We shelved the project for the day, but that afternoon there was a crash from the room the computer was in. I returned to the room to find that the screen had fallen off the machine, traumatically disconnecting the cables.

Remarkably, the screen and cables were still functional. I took the drive out and put it in an external test jig and verified that it was defective. I got an RFC to return it to OWC, and they assured me that they would include a new adhesive kit. I put the old HDD in so Josh wouldn’t be without a machine and taped the display back on with blue painter tape on the exterior, leaving the failed adhesive on the interior.

The new drive arrived about a week later without the adhesive. Josh was anxious to have his computer back, so we tested and installed the new SSD and put the screen back with external blue painter tape again. It had kind of a steampunk look to it. For some reason, I had the notion that OWC was shipping the adhesive under separate cover, but it never came. I wrote and asked them about it, and they eventually shipped it.

I went through the whole remove-old-adhesive apply-new-adhesive dance again, but this time also taped the screen back with the blue painter tape. I left that on for a week to give the adhesive time to set, then replaced it with black electrical tape which would stretch and reveal if the internal adhesive was failing but (I hoped) prevent traumatic separation. This time, it held, and I eventually (with some trepidation) removed all the exterior tape.

In the end, we were successful in getting the HDD replaced with an SSD, but I’m afraid I failed at helping Josh become more comfortable with doing his own computer repair. OWC stood behind their product, but the fact that I essentially had to do the replacement four times meant that I would have been much happier just replacing the machine or having a shop do the replacement (though whether they would have detected the problem with the first SSD is hard to guess).

I guess the moral of this long-winded story is that it is doable, not too terribly difficult, but I would absolutely tape the display on for a week after re-installing it with new adhesive and don’t expect it to be a quick and simple task.


If I were you, I’d do a hybrid. Continue booting from the MBA it get the external drive and wait for Apple to release a new iMac. If it was me, though, I’d just buy a new iMac and not worry too much about a potential update in the fall. And you’ve said you’re not too concerned about CPU power anyway.

There’s one independent shop in town that I’d trust to take a look at it, but I have no idea if they’re open. Might be a bit weird to do an arms-length handoff. :slight_smile:

True, though there’s the other side too, which is that you often don’t want to buy the very first machine after a major processor switch.

I probably will write it up, and yes, it’s definitely all a business expense!

Great advice, and thanks for the real-world warnings about what could go wrong. I am a little worried about OWC’s quality too, since I’ve had a few things from them go bad and need to be replaced under warranty (including RAM). They’ve always been good about replacements, but I’d rather have it not happen to start.

True, though part of the reason for that is that I usually buy the top-of-the-line model to ensure that I’ll be able to use it for as long as possible. Given that my current Macs are 8 and 6 years old, I’m pretty happy with that strategy. (And to be fair, I would have bought a new laptop before this except for the horrible butterfly keyboards.)


I don’t know about your shop, but Louis Rossman has talked about what his shop is doing. Customers put the computer on a table and then go sit on a bench a significant distance away. The tech wipes down the equipment with isopropyl alcohol before going any further. He also makes a point of sterilizing everything (again, with ispropyl alcohol) after completing work, before handing it back to the customer.

As for what I would do in your situation, I would be too scared to open and close an iMac myself. If I didn’t have a convenient independent repair shop, I’d probably switch to an external SSD and pretend the internal one no longer exists. Preferably via a Thunderbolt enclosure, but I think USB3 (attached directly with no hubs or other devices sharing the port) would probably be good enough if Thunderbolt was too expensive.


I’m a MBP+external screen (docking station) guy so I totally get the portable Mac idea. But I would caution against using a MBA as a main machine for more than Office and web. It’s a sweet machine at a good price no doubt, but it does have its limitations.

So if the current 16" MBP plus an external screen (wasn’t there something like TDM to use an iMac as an external display?) isn’t your thing, the portable Mac route is basically blocked since I wouldn’t buy a 13" MBP so shortly before the widely expected refresh.

I wouldn’t like to have my main Mac serviced either, because I don’t want to be without it for several days. Plus, in your case it’s from 2014! C’mon man. You’re almost as bad as me with my 2013 MBP. :slight_smile:

So if I were you (again assuming you don’t want a 16" MBP) I’d buy a nice and fast external SSD. Of course a good SATA SSD with a USB-C 3.1 dock would be sweet, but your iMac from 2014 doesn’t do that. Maybe TB2? Don’t now how economical that is. Whatever you choose, you’d be able to use this disk as a fast boot volume until the next iMac refresh. Then you buy that iMac and keep on using this nice SSD as external storage or backup or TM or whatever.

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One more thing. If you do decide to buy a new Mac but you’re not entirely sure which one, just go for it. In my experience Apple is a total straight-shooter when it comes to returns.

Choose a new Mac and have it shipped to your door. When it arrives put it through its paces, try out all aspects of your workflow. After 14 days you either keep it or give Apple a call. In the latter case, they will help you set up a pickup at your door (no questions asked), return shipment will be fast, and they will then reimburse you within few days. In my experience that has worked perfectly and there were no shenanigans at all. In fact, I was baffled how quickly I had my money back in hand.

If it really turns out you made the wrong call, you can always opt for another Mac later. Getting your own hands-on experience with a new Mac on your own workflow in my book beats reading all the reviews you can find. And I say that as a guy who loves reading good reviews (such as the ones on TidBITS). :slight_smile: :+1:

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I’m actually a full-on desktop guy—27-inch iMac with a 27-inch Thunderbolt Display. So for me, laptops are small travel machines, and performance is never paramount. But you’re right about not wanting to buy any laptop before we see what replaces the current 13-inch MacBook Pro.

You’re thinking of Target Display Mode, but that worked only on older, pre-Retina iMacs. Sadly, since I’d love to use this iMac as a display in the future.

Agreed. And doing the repair myself, while probably in my skill set, does have the downside of me potentially screwing up and breaking the machine entirely.

It’s working surprisingly well while booted from the 2012 MacBook Air—it may actually feel a little faster, but I suspect that’s because there’s less crud loading. I do have trouble with installing too much software in my line of work.

As with @Shamino, this is where I’m leaning now. Just have to figure out the best connectivity for the price.

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Adam, I don’t know how good this thing is, but I wonder if this might be the most economical way to get a fast SATA SSD hooked up to your TB2 iMac (eSATA to SATA is just a $5 cable) without sacrificing performance.

I would buy the fastest external enclosure with an SSD and ignore the internal drive. I would then continue to use the machine until Apple determines that it can no longer be upgraded to the latest macOS or the overall performance is inadequate.

One client, experienced with external drives, followed this advice early this century, eventually buying a new 27" Retina model to install a new macOS. In another case, a four bay Thunderbolt enclosure found on sale by OWC ( with an SSD for boot drive was attached to a Mac mini with a 5400 rpm internal hard drive. I have not opened a Mac mini for storage replacement since.

It really comes down to the value of upgrading your current iMac versus the cost of a new system, including performance requirements and macOS upgrade lifetimes.

Remarkable that Adam is in the same situation as me and coincidentally considering the identical options, it is so helpful to read all the posts and the knowledge gained will certainly help me in my final decision making. At the moment I am running my 27in iMac off an external 500Gb SSD which is small and very neat, the Macintosh HD just sits there not earning its keep at all though I have dumped a load of photos and movies on the HDD portion.
One advantage of running off an external SSD is that when I travel with my MBA I can hook up and boot from that too if needs be. Interesting to read your comments about the 13in MBP as that is the direction in which I am leaning.
Stay well all of you in the US the numbers are quite scary but I know you will overcome this.

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IMO, if you’re going to buy a SATA drive, then USB3 is more than adequate. SATA 3 tops out a 6 Gbit/s. USB 3.0 tops out a 5 Gbit/s, which is a little less than SATA’s top speed, but probably good enough. USB 3.1 Gen 2 tops out at 10 Gbit/s, which can easily keep up with SATA.

The reason for wanting Thunderbolt is that an NVMe drive uses up to four lanes of PCIe for connectivity. At slightly less than 8Gbit/s per lane for PCIe 3.0 devices, an NVMe drive can easily exceed USB’s maximum throughput. Thunderbolt 3, however, offers up to 32 Gbit/s of PCIe connectivity (thanks to Intel chipsets on the Mac motherboard that supply four lanes per pair of TB3 interfaces).

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David, you’re absolutely right. But problem is, Adam’s 2014 iMac just can’t do TB3 or USB-C 3.1 Gen2. I’d assume the best you can do there is SATA->TB2 but I’d be anxious to hear if anybody here has something better for a pre-TB3 Mac.

The last time I had to replace the drive in one of the thin iMacs, I asked the techie to NOT use the double-faced adhesive but, instead, use 2" wide clear packing tape on the sides and top (obviously, none where the camera and light sensor are). If there’s ever a need to get back in, it may be easily done.

There’s a special place in Hell reserved for Jony Ive; it’s a sealed room with no doors.

The main reason I’d get a Thunderbolt 3 dock would be to get the benefit of Thunderbolt 2 performance on this iMac, and then have better performance with the next one.

However, a USB 3 dock may be more generally useful since we have other old Macs as well. And it’s not inconceivable I’d want to connect it to an iOS device someday for testing.

TB3 is of course awesome. In your case especially with its TB2 backwards compatibility. But I have yet to come across a halfway decent TB3 SATA dock that’s not outrageously expensive. I’d be happy to be proven wrong here though.

USB3 in your case is probably the more cost effective solution. But beware that your iMac doesn’t do 3.1 so it will be limited to 5 Gbps peak (and IIRC no UAS ) which in reality will translate to something like 320 MB/s at best. While that is still fast, just beware that it will bottleneck decent SSDs that you can readily buy today. Likely not a problem if you’re not into very high performance, but something to keep in mind when you do go out and buy the SSD. Unless you’re buying with future use in mind, you could probably choose a somewhat older and less expensive SSD simply because the extra oomph of the newer models would be lost at your USB interface.

Well, USB 3.0’s top speed of 5 Gbit/s is 83% of SATA3’s maximum speed. Which may still be good enough, and it is going to be a pretty low-cost option these days.

As for Thunderbolt, even TB2 may be just fine with an NVMe drive. Yes, you will be limited to 20 Gbit/s (maybe only 16) instead of TB3’s top PCIe speed of 32 Gbit/s, but still much faster than SATA. The only downside, of course, is the price. An Thunderbolt-NVMe enclosure will cost more than a USB-SATA enclosure, and you need to add a TB3-TB2 adapter if you can’t find an enclosure with native TB2 support.

No, note that’s just the bus’s peak bandwidth. Read the rest of my post. AFAIA, the fastest SSD speeds measured on Macs over 3.0 are about 320 MB/s which is substantially lower than what people achieve over TB2 or TB3 or USB 3.1 Gen2. Pretty much any quality SSD you buy today would be bottlenecked by that.

Now that indeed is not a problem if say Adam just wanted it as stopgap measure until his fancy new iMac gets released. But if you’re putting real money into a quality SSD that you expect to perform according to its specs, you need a faster bus. Since Adam’s 2014 iMac doesn’t have a better USB, I’m afraid TB is his only option. That will no doubt be a bit more costly. If that’s worth it really depends on how much performance he needs from this SSD and over what period of time.

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