Case Study · Apple iMac
A clicking Seagate from an iMac. 99.95% of the data came back.
A 1TB Seagate BarraCuda 7200.12, pulled from a failed Apple iMac, arrived clicking and barely responsive. A donor head swap in our cleanroom got it reading again.
Background
Replaced by an Apple Repair Centre — but the data stayed behind.
iMacs tend to fail the same way: an internal hard drive nearing the end of its working life, or damaged by a knock. This one had already been pulled out.
An Apple Repair Centre had fitted the iMac with a new hard drive, but had no way of getting the customer's data off the old one. The failed drive was posted to our Belfast laboratory by Royal Mail on its own.
It was a 1TB Seagate BarraCuda 7200.12 — a mechanism we see often, whether it started life inside an iMac, a MacBook, a Mac mini or a Windows desktop. On arrival, the drive was clicking and responding very slowly to commands.
Diagnosis
Red sectors, and a warning not to push it further.
A first, careful imaging attempt told us exactly what we were dealing with before we risked anything further.
The first pass threw up large numbers of red, unreadable sectors across the surface — the signature of a read/write head problem on this drive family. Continuing to read from the drive in that state risked permanent damage to the platters, so imaging was stopped there.
The fix for failed heads is a donor head swap, done under cleanroom conditions — not something to attempt outside a lab. Videos online make it look straightforward; in practice, a successful outcome from a home attempt is very unlikely. The same goes for putting a failing drive in the freezer: it does not fix a mechanical fault, and the condensation it causes usually makes the recovery harder, not easier.
In the lab
From failed heads to a stable image.
- 01
Diagnostic imaging
An initial imaging pass identified extensive red, unreadable sectors — pointing to failed read/write heads rather than logical corruption.
- 02
Cleanroom head swap
The Seagate 7200.12 was mounted alongside a matching donor drive in the cleanroom, and its failed heads were replaced with heads from the donor.
- 03
Stable re-imaging
With new heads fitted, the drive imaged cleanly and consistently — read using DeepSpar disk imaging tools, tracking each sector as it came back good.
- 04
Verified recovery
The image was checked against the original file structure to confirm the recovered data was complete and usable before it was returned.
Outcome
99.9533% of the data recovered.
Once the heads were replaced, the picture changed completely.
Where the first attempt returned mostly red sectors, re-imaging after the head swap returned overwhelmingly green — the sign that a sector has read cleanly. With the new heads in place, we recovered 99.9533% of all data from the drive.
Head replacements are more involved than a straightforward logical recovery: they need a matched donor mechanism, cleanroom conditions and more time, which is reflected in the cost — a job of this kind runs to around £350 + VAT. It is also, as this case shows, very often the difference between a "repaired but empty" iMac and getting everything back.
Power it down and stop using it. Send it to our Belfast laboratory for an honest diagnosis and a fixed quote before any recovery work begins.