Data Recovery Case File · Portable Drives · A Precise Kind of Silence

It Never Appears at All

His enquiry included a qualifier that most people would leave out, and it does real diagnostic work. A USB external drive: "when plugged in it starts to spin up but never completes, and never shows up in the OS — even as an unrecognised device." That last clause is the useful one. Operating systems announce every device that introduces itself, including ones they cannot identify or use, listing them as unknown. A device that does not even manage that has failed before the introduction begins — and combined with a spin-up that starts and stops, it points somewhere specific.

The decode: what total absence rules out, and where that leaves it

Why "not even as an unrecognised device" matters: when anything is plugged into a USB port, the host supplies power and waits for the device to introduce itself. If that exchange completes, the system lists the device — even where it has no driver, cannot identify the model, or cannot use it, in which case it appears as unknown. So an unknown device in the list is evidence that the introduction succeeded. His drive produces nothing at all, which means the exchange never happened. That eliminates every fault that occurs after enumeration — filesystem damage, partition problems, translation-layer failures — in a single observation.

What the partial spin-up adds: the drive is receiving power and attempting to start, so the enclosure is passing current through and the motor is being driven. A spin-up that begins and does not complete usually means one of two things: the drive is being starved of current and stalls before reaching speed, or it is reaching a fault during its start-up sequence and shutting down.

Why current is the first suspect, and it is free to test: spinning a mechanical drive up from stationary is the most current-hungry moment in its operation, considerably more than running once at speed. Ports vary in what they actually deliver — laptops on battery, hubs, docks, long or thin cables all reduce it. A drive that is marginal for current does exactly this: starts, stalls, and never gets far enough to announce itself. A short good-quality cable, a port directly on the machine, mains power rather than battery, and a Y-cable or powered hub if available will settle it in minutes.

What remains if power is confirmed good: the enclosure bridge may have failed — the board that converts the drive's native connection to USB. If that is dead, no enumeration can occur regardless of the drive's condition, and the drive itself may be entirely healthy behind it. Or the drive is failing during its own readiness sequence, which is a drive-level fault.

Why measurement rather than repetition: the way to separate these is to measure what the drive draws on a controlled supply — a drive that draws nothing has a power-path fault, one that draws heavily and stalls is fighting resistance. Repeated plugging achieves nothing and each stalled spin-up under load is harder on the mechanism than not starting at all.

On the bench

Supply and cable were eliminated before the drive was implicated, since a drive starved of current behaves exactly like a dead one and the test costs nothing. Current draw was then measured on a controlled supply rather than a host port, distinguishing a drive that draws nothing from one stalling under load — in a single reading rather than by repeated cycling. The enclosure bridge was assessed separately from the drive, since a failed bridge prevents enumeration regardless of the drive's condition, and where that proved to be the fault the drive was read on a native connection.

The outcome

The supply eliminated, the bridge assessed separately and the drive read on a native connection. 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 whose drive never appears at all: mentioning that it does not even show as an unknown device is genuinely useful, because systems list every device that introduces itself successfully — so total absence means the introduction never happened, which rules out every fault that occurs after it; combined with a spin-up that starts and stops, that points at current first, then at the enclosure bridge. Test the power before assuming the worst.

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.