Data Recovery Case File · Desktop Externals & Aging Drives · The Light Is Cycling
A Pulsing Indicator Is a Device Starting Over
His enquiry describes a light behaving in a way that is easy to overlook and worth reading. A ten-year-old external drive holding pictures from old phones: "I've tried to turn it on and it won't power up. I've checked the power adapter and that works fine. When it's connected to the drive there is an intermittent flashing light on the front but it doesn't c"ome up. A steady light and a pulsing one report different things — and an indicator that flashes intermittently on a device that never starts usually means the device is trying repeatedly and failing each time.
| Media | External hard drive of approximately ten years — not completing start-up; indicator pulsing intermittently; power adapter confirmed functional |
| Reported situation | Drive of approximately ten years failing to power up · power adapter tested and confirmed working · indicator flashing intermittently when connected · drive not starting · photographic content from previous devices held |
| Fault class | Repeated failed initialisation cycle — supply capability or drive start-up failure indicated; dormancy effects present |
| Equipment used | No further power attempts · flashing interval recorded as evidence of cyclic retry · drive removed from the enclosure and current draw measured on a controlled bench supply across the range · dormancy effects assessed alongside · laminar flow bench inspection before any spin attempt where indicated |
The decode: steady, off, and flashing
What a steady light usually means: power has arrived and the enclosure's supply stage is delivering. It says nothing about whether anything is working, which is why this archive is generally dismissive of indicators.
What no light means: power is not reaching the indicator, so the fault is at the supply, the adapter, the socket, or the enclosure's power stage.
What an intermittent flash means, and it is the informative one: the device is powering up, attempting something, failing, and starting over. The light comes on with each attempt and goes out when the attempt collapses — so the interval between flashes is the length of one failed cycle. That is a device in a retry loop rather than a device that is simply off.
What causes the loop: most often the drive drawing more current than the supply can deliver. A mechanism that is stiff — and a ten-year-old drive that has been stored is a strong candidate — demands a large current surge to start turning. Where the supply cannot sustain it, voltage sags, the enclosure's protection cuts in, everything resets, and the cycle repeats. The adapter testing fine under no load says nothing about its behaviour under a heavy one.
Why the drive's age is central: lubricant in the spindle bearing migrates and thickens over years, so a bearing that turned freely can become genuinely stiff. Heads resting on a platter can adhere. Both increase the torque required to start, which is precisely what turns a marginal supply into a cycling one.
Why that is a hopeful reading and also a reason to stop: if the drive is stiff rather than damaged, the fault is mechanical and addressable. But every cycle applies a starting surge to a mechanism that will not turn — and if the heads are adhered, each attempt drags them across the surface. A cycling drive is being asked to fail repeatedly, several times a minute.
What to report: the interval. A flash every second or two describes a fast retry loop; one every several seconds describes a longer attempt before collapse. Both are useful and neither costs anything to observe once.
On the bench
No further power attempts were made, a cycling device applying a starting surge to a mechanism that will not turn several times a minute. The flashing interval was recorded as evidence of cyclic retry — an indicator illuminating with each attempt and extinguishing as it collapses, so the interval measures one failed cycle. The drive was removed from the enclosure and current draw measured on a controlled bench supply across the range, an adapter testing fine unloaded revealing nothing about its behaviour under a starting surge. Dormancy effects were assessed alongside, and inspection ran under the laminar flow bench before any spin attempt where indicated.
The outcome
The retry cycle characterised, draw measured across the supply range and dormancy assessed alongside the original fault. 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: a steady light means power arrived, no light means it did not, and a flashing one means the device is starting, failing and starting again. Most often that is a drive demanding more current to turn than the supply can sustain — and a ten-year-old mechanism is stiff.
Drive whose light flashes rather than staying on
Stop powering it, and note the interval between flashes before you do — that measures one failed start-up cycle and it's genuinely useful. A steady light means power arrived; no light means it didn't; a pulsing one means the device is powering up, attempting something, failing and starting over several times a minute. The usual cause is the drive demanding more current to start turning than the supply can sustain, at which point voltage sags, protection cuts in and everything resets. Your adapter testing fine tells you little, because it was tested unloaded. On a drive of ten years the mechanism is likely stiff from thickened lubricant, which is exactly what makes the surge too large.
Note the interval, then stop — call Guildford Data Recovery on 01483 901310; retry cycle characterised, draw measured across the supply range on a controlled bench supply, dormancy assessed alongside.
Request a quote online →
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.