Chosen Solution
Some genius married to my wife pulled the HDD out of her iMac and sold the rest for parts. Local store wants us to send them the SSD. I’ve messaged the parties concerned, but I’m thinking it’s an impossibility. It seems like the HDD should hold some data, but also that divorcing the fusion drives could really wrench the cogs. I’ve got an external HDD cage and am willing to buy whatever to make this work. I’ve seen some recommendations to boot in Linux, which I’ve never done, but can learn no problem. Want to make sure that could be the solve before diving in, though. I’ve got a Windows machine and her current iMac. Is there any hope for me here?
Ah! A Fusion Drive mess up! A Fusion Drive is when the two drives (HDD and the hidden SSD on the back side of the logic board are tied together via software (macOS). The SSD is just a cache drive to the HDD, it is holding fragments of the apps and files you have used often so you may want to remove it if you are selling your system if the system is broken. If you are selling you should leave the drives in the system, backing up your stuff using TimeMachine so you can restore your apps and junk to your new Mac system. Then use Disk Utility to wipe your drives. The Fusion Drive SSD is quite small (128 GB) almost useless. It doesn’t offer them any benefit without the HDD. Even still it doesn’t have your files the HDD holds them! The OS only copies often accessed data blocks to the SSD from the HDD. If the data is updated it is written to the HDD and then copied to the SSD if the block is often accessed. So it’s nothing more than a copy of some elements (blocks) of the HDD’s data and the data within the HDD is 100% complete, why do they think they need it?
CONFIRMED! A host Mac can mount an APFS formatted Fusion Drive Volume where the Hard Drive and SSD are externally connected via USB. The external Fusion Drive volume will behave like any other startup volume or externally connected drive/volume. I had no issues connecting to a host that also had a Fusion Drive. Notes: Target Disk Mode is a better option if your source Mac can boot (you don’t need a working display).You will need a USB 3 SATA adapter/cable to connect the removed Hard Drive to the host Mac.23.5" iMacs use 2.5" laptop drives; the SATA bus supplies adequate power.27" iMacs use full-sized (3.5") drives that need additional power. This adapter can be used with either type of drive—it includes a 12V power adapter that connects to the SATA adapter ($20 / SATA to USB 3.0, Neeyer SATA III Hard Drive Adapter Cable for 3.5/2.5 Inch HDD/SSD with 12V/2A Power Adapter, 20 Inch).Unsure if the source Mac had a Fusion Drive?A Fusion Drive is simply a configuration that utilizes a Hard Drive and an SSD to create a storage volume.Connect the removed Hard Drive to the host Mac—if the drive doesn’t mount, it may be part of a Fusion Drive configuration. Or it could be damaged!Using Terminal, type ‘diskutil list’—if the Hard Drive is part of an APFS Fusion Drive configuration, it should still appear as a connected drive, but it will not have a named volume like ‘Macintosh HD’. APFS formatting should be apparent.If you attempt to mount a drive that’s part of a Fusion Drive configuration, you may see the following error: ‘diskmanagement disenter error -119930868’.The SSD from the source Mac will be needed to complete the Fusion Drive volume—without both functional components, the volume cannot be read. The SSD blade is located on the back of the Logic Board, and can be challenging to remove—iFixit guides are available.You will also need an enclosure for the SSD—OWC has compatible enclosures here. Check Mac compatibility carefully. Later iMacs use different pin configurations than older Macs. I used the this enclosure for the SSD blade from a Late 2012 27" iMac ($60 / OWC Envoy Pro 0GB Portable Bus-Powered USB 3.1 Gen 1 Cable, Storage Solution for 2012-2013 MacBook Pro w/ Retina Display).Finally, shutdown the host Mac, connect both the Hard Drive and SSD, and restart. The external Fusion Drive should mount like any other external volume—you can browse and copy files. Cloning a Fusion Drive volume is a headache, but Carbon Copy Cloner works well and offers a fully functional demo.Option boot to the Startup manager to use the external Fusion Drive as the startup volume.Best for coping / cloning only—then disconnect or reuse the drives.
