Data Recovery Case File · NAS & Network Storage · Not the Same Problem Twice

One Does Nothing, One Lasts Five Seconds

This enquiry came from a film production office doing something sensible and finding trouble. "During a checkup of the drives, I noticed that two of the drives do not work. The first, a desktop external, does not turn on at all. The second, an 8TB dual-drive storage system, is on for about 5 seconds when it is plugged in but then dies again." Two failures discovered together invite the assumption of a common cause. These are almost certainly unrelated, and they are different faults with very different prices — one of which is frequently the cheapest outcome in this trade. Discovering them together is a consequence of checking, not of anything shared.

The decode: the two faults, and the cheap one first

The silent unit — start with the power supply. A desktop external that shows no response at all is most often failed at its external power adapter, which is the single commonest fault on mains-powered drives and costs nothing to establish. After that, the enclosure's own board. Only after both of those is the drive itself implicated — and in the first two cases the drive is perfectly healthy and the data untouched. It is genuinely worth checking before anything else, with one caution: a substitute adapter must match voltage, polarity and current rating exactly, because the wrong one can damage a healthy drive.

The five-second unit — what a brief run then a shutdown means. That pattern is characteristic and different. A unit that powers, runs briefly and then cuts out is usually a protection response: the power supply or the enclosure detects excessive current draw and shuts down to protect itself. On a dual-drive unit the commonest cause is one of the two drives drawing far more than it should — a seized motor straining to start, or a shorted board — which pulls the whole unit down within seconds. So the fault is likely to be one member, not the enclosure, and the other member may be entirely healthy.

Why that matters for the array: a two-drive unit may be configured striped, in which case both members are needed, or mirrored, in which case either alone holds a full copy. If it is mirrored and only one drive has failed, the healthy member holds everything — which is a very good outcome and one that is invisible while the enclosure keeps shutting down. Removing both drives and assessing them individually is the way to find out, and it should be done rather than continuing to power the unit.

Why repeated attempts are costly here specifically: if a drive is drawing excessive current because its motor is seized, each power-up is that motor straining at full torque against a mechanism that will not turn — and if the heads are adhered to a platter, it is dragging them across the surface. The five-second cycle is not harmless observation; it is the damaging event, repeated.

Why finding two at once is not a pattern: worth saying, because it prompts anxiety about the rest of the shelf. Drives bought at the same time, stored in the same room and used for the same project do age together — so it is worth checking the others. But two different faults appearing on the same day is the ordinary consequence of nobody having checked for a while, rather than evidence of a common cause.

On the bench

The power supplies were eliminated before either drive was implicated, since a unit that fails for want of an adapter should not be quoted as a recovery. The dual-drive unit was not powered further, because a five-second shutdown is a protection response to excessive draw and each cycle repeats whatever is causing it. Both members were removed, labelled by bay, and imaged individually write-blocked — establishing which member was faulty and whether the surviving one held a complete copy. The array was assembled offline from the images where both were required, and the contents verified.

The outcome

The supplies eliminated first, the members assessed individually and the array assembled offline from images. Free assessment, one fixed written figure including VAT; where a drive has to be opened, 50% of parts and labour is payable upfront with the balance only on success — otherwise no recovery, no fee. The decode, for anyone with two dead drives: they are probably unrelated, and finding them together is a consequence of checking rather than a common cause; a unit that does nothing at all is most often a failed external power adapter, which costs nothing to check and leaves the drive untouched; a unit that runs for a few seconds and cuts out is a protection response to excessive current draw, usually caused by one failing member — so stop power-cycling it, take both drives out and assess them separately.

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.