Case Study — Hard Drive Head Crash
A full head crash, and an honest answer.
A Hitachi (HGST) 750GB hard drive arrived at our Belfast laboratory completely unresponsive. What we found was a full head crash — and a reminder that, however good the lab, not every drive can be brought back.
The case
An HGST Hitachi 750GB that stopped responding.
The drive in question was a 750GB HGST-manufactured Hitachi hard disk drive, sent in after it stopped responding to its host system entirely.
Cases like this make up a steady share of what comes through the door: a drive that once worked normally, then simply stops being seen. On examination, this one showed the signature of a full head crash — the read/write heads had made direct contact with the platter surface, rather than floating fractions of a millimetre above it as they should.
We cover this case openly, including in video, because it illustrates something worth knowing before you ever need a data recovery lab: some damage is genuinely beyond recovery, and an honest lab will tell you so rather than promise otherwise.
Diagnosis
Why some head crashes can't be repaired.
Our most effective recovery techniques rely on part-replacement in a cleanroom environment — swapping the heads, the electronics board, or the firmware and parameter tables for a matching donor part, then reading the original platters with working components. Done carefully, this succeeds on roughly 40–60% of the physical failures we see.
That is not the near-100% success rate some data recovery marketing implies. It also is not a fixed number — for some drive models and failure modes, success rates are close to zero, however good the equipment. In this case, the head contact with the Hitachi 750GB's platters had gone far enough that no head swap or donor part could recover data from the affected surface. The damage was physical and permanent, not something firmware or electronics could work around.
We would rather say that plainly than take on a job we know cannot succeed.
What not to do
How a head crash gets worse.
- 01
Don't let it keep spinning
If a drive has been dropped or knocked and starts clicking or fails to respond, don't try to power it on repeatedly or let it run "just in case." Every extra spin risks turning a partial head crash into a total one.
- 02
Don't try software recovery first
Software tools read the drive through the same damaged heads that caused the fault. On a physically failing drive, this rarely works — and it commonly leaves the drive in worse condition than when it arrived.
- 03
Don't hand it to a general repair shop
A local computer shop can be right for many things, but a mechanically failing drive needs cleanroom handling and the right diagnostic hardware from the first power-on, not the last resort after other attempts have failed.
- 04
Don't freeze it
There is no documented case of freezing a hard drive fixing a fault. It risks condensation and corrosion inside the drive, adds nothing to the chances of recovery, and makes the job that follows more difficult and more expensive.
The result
Not every case ends in recovered data.
This Hitachi 750GB drive could not be recovered. The head crash had damaged the platter surface itself, beyond what part-replacement or imaging could work around.
We take on a lot of failed hard drives, and on most of them the success rate is high. But a lab that only shows its wins isn't giving you the full picture. If a drive has failed, the single biggest factor in whether it can be saved is what happens to it between the fault and the point it reaches a specialist — powered off, untouched, and assessed before anyone experiments on it.
Power it down and get an honest assessment before anyone touches it further — what can be recovered, what can't, and what it will cost.