Data Recovery Case File · Portable Drives · Height Is Not the Measure

Off a Chair, and That Was Enough

His enquiry contained an apologetic detail that people often add, as though the fall were too small to count. An external hard disk that "fell off a chair on to the floor. Now when I turn on the disk there is a rasping sound. Sounds like the head is stuck. It has old photos from 2008 to 2009 so I would really like to get them back." He is close to right about the mechanism and understandably wrong about the significance of the height. A drive does not need to fall far — what matters is whether it was running, and a rasping sound means it was.

The decode: what the sound is, and why a chair was plenty

Why the height is not the measure: the state of the drive at the moment of impact is. A drive that is switched off has its heads parked away from the platter surfaces, secured on a ramp or landing zone, and can survive being knocked about far more than people expect. A drive that is running has its heads flying microscopically above spinning surfaces, and any sudden movement can bring them into contact. Desk height, chair height and a few inches are all sufficient. The reason short falls damage drives so often is simply that a drive being used is a drive that is running.

What a rasping sound means: he is nearly right and the distinction matters. A stuck head produces a beep or a straining tone, because the motor cannot turn the stack at all. A rasping sound means the platters are turning and something is interfering as they do — a damaged head contacting a surface, a displaced assembly dragging, or debris circulating within the enclosure. So the mechanism is not stuck; it is running and being damaged while it runs.

Why that makes powering it the expensive thing: this is the crucial practical point. If a head is in contact with a platter, every second of rotation drags it across the magnetic surface where his photographs live, removing coating and generating particles that circulate and damage more. A stuck drive that will not turn is, oddly, safer than a rasping one that will. The number of times it is switched on from here is the largest remaining variable.

Why the age of the material matters to the approach: photographs from a single two-year period, fifteen years ago, are almost certainly the only copies. They predate routine phone backup and cloud sync, and they cannot be reshot. That justifies inspecting before powering rather than testing first, and imaging in one supervised session with the recovered heads at their most reliable.

What not to do: the remedies that circulate for exactly this sound. Freezing introduces condensation onto surfaces that are already being scored. Tapping deliberately moves a head assembly that is already in the wrong place. Both are offered as fixes for drives that make noises, and both are worse than doing nothing.

On the bench

The drive was not powered again, since a rasping sound means the platters are turning while something interferes — the one state in which every second of rotation removes more of the surface. It was opened under the laminar flow bench and the head assembly, platter surfaces and spindle inspected before any spin attempt, with surface scoring assessed and mapped so that the extent of contact damage was known before anything turned. Matched donor parts were fitted, and imaging ran on the PC-3000 Express under Data Extractor, head-mapped and prioritised to the photographs, in one supervised session.

The outcome

The mechanism inspected and scoring mapped before any rotation, serviced with matched parts and the photographs imaged in one supervised session. Free assessment, one fixed written figure including VAT, 50% of parts and labour upfront with the balance only on successful recovery. The decode, for anyone whose drive fell a short way: height is not the measure — a drive switched off has its heads parked and survives a great deal, while a running drive has them flying microscopically above the surfaces, so a chair is ample. And a rasp is not a stuck head: a stuck drive beeps because nothing turns, whereas rasping means the platters are turning and something is interfering, which makes every power-up costly.

Our case files are drawn from genuine enquiries received by our laboratory over the past ten years, anonymised to protect client confidentiality. Each one describes the diagnostic and recovery procedure our engineers apply to that fault, using the equipment listed.