It fell, and since then nothing recognises it and it makes the same sound over and over whenever it is plugged in. The repetition is the diagnosis. A drive that repeats a sound is repeating an action, and the action is a head stack trying to read and failing. Out to the platter, no servo pattern found, back to the ramp, start again. Each cycle is another pass across the surface your files are written on with heads that are no longer flying properly. That is the whole of the fault and it is a common one after impact, because portable drives are usually carried while they are running and a fall onto a hard floor delivers a shock in the hundreds of g. The platters are generally sound at this point. Whether they stay sound depends entirely on how many more times it gets plugged in.
| Media | External hard drive, not recognised since a fall, producing a repeating sound each time it is connected. |
| Reported situation | External drive · not recognised after a fall · makes a repetitive sound whenever it is connected · recovery sought. |
| Fault class | Head fault caused by impact. The repeating sound is the head stack failing to read and retrying, so the drive never presents itself. The platter data is normally intact and is reached with matched donor heads under laminar flow. Repeated power-ups are the hazard. |
| Equipment used | Not run again given the fall and the sound · lifted from its enclosure and run off a bench supply with the current limited, the retry pattern characterised without letting it continue · opened under laminar flow in filtered air, with the head stack and the platter surfaces examined at magnification, a matched donor head stack installed and the alignment set · imaged on DeepSpar with PC-3000 UDMA driving the drive, data located and validated in R-Studio. |
Hard drives are not supposed to make repeating noises and the fact that they can is a design consequence rather than a defect. When a head stack cannot locate the servo pattern that tells it where it is on the platter, the firmware retries: retract to the ramp, sweep out, look again. The sound is the sweep and the retract, and it repeats because the firmware is stubborn about it.
After a fall the usual reason for that failure is head damage. A head is a tiny structure flying nanometres above a surface moving at speed, and an impact puts it into contact. Sometimes the head is bent, sometimes the slider is chipped, sometimes debris from the contact is now circulating inside the sealed casing. In all three cases it cannot read, so it retries, so it makes the noise.
The reason to stop immediately is straightforward physics. A damaged head passing over the platter can score it, and a scored track is unreadable by any head, donor or otherwise. Fitting new heads to a drive with clean platters produces a complete image. Fitting new heads to a drive whose platters have been scored for a fortnight produces whatever survived between the scratches, and no amount of money changes that.
So the honest prognosis rests on the surfaces, and the surfaces are inspected under the microscope at magnification once the drive is open. Heads replaced over sound platters give a full recovery. Heads replaced over damaged ones give a partial. The recoverable extent is established and confirmed before anything is charged, after a free assessment that completes within 2 working days of arrival.
It was not powered again on arrival, because the combination of a fall and a repeating sound needs no further confirmation. It was taken out of its enclosure and run from a bench supply with the current limited, where the retry pattern was characterised in seconds rather than by letting it work at it. It was opened under laminar flow and the head stack and platter surfaces examined under the microscope at magnification: the heads had failed, and the platter condition determined what was realistic. A matched donor head stack was fitted, the alignment set, and the drive imaged on DeepSpar with PC-3000 UDMA driving it. The filesystem was reassembled in R-Studio off the image and the contents opened and checked before anything went to fresh media.
Heads swapped under laminar flow, the drive then imaged, the data brought back onto fresh media. Assessment free, and one fixed written figure with VAT in it before the casing was opened. Physical work consuming a donor and clean-air hours, so half of it was settled before that stage with the balance owed only on the result. It is worth putting the general rule down plainly, because it applies to every dropped drive that reaches this bench: the fall sets the fault, and the number of power-ups afterwards sets the outcome. One is unavoidable. Thirty is a choice.
Unplug it now and leave it unplugged. A repeating sound is a repeating attempt, and each attempt is damaged heads passing over the surface holding your files. Do not try it on another computer to make sure, do not swap the lead for another one, and do not leave it plugged in while you read about it. Ignore every home remedy on the internet — freezing a drive does nothing except add condensation, and tapping it makes contact damage worse rather than better. Do not open it. Box it so it cannot move, note roughly how many times it has been powered since the fall, and send it tracked. That number is genuinely useful and it affects what the assessment expects to find.
Each file below comes from a genuine enquiry taken from households and firms across Aberdeen, Aberdeenshire and the wider north-east, anonymised so nobody can be identified. Each one sets out how the fault was reasoned through, what was done about it, and which equipment did the work.
A shop that says a part inside is broken has read a dropped drive correctly — that part is the head assembly, and it is changed in clean air
A socket that has been strained once and then yanked has failed at the connection, and the drive is read past it rather than through it
A drive that tries to start and gets no further has failed at the heads — the light and the noise are the last two things it can still do
Assessment is free and takes 2 working days at most once it lands, the figure is fixed in writing, and logical work carries no fix no fee. Begin online, or lift the phone.