The instinct when a drive disappears is to start swapping cables. Give it sixty seconds first. Plug the drive in, keep your hands off it, and pay attention to three things: whether a light comes on, whether you can feel the faint tremor of platters turning through the case, and whether any sound is coming out of it that was not there a month ago. Those three observations sort nearly every vanished drive into one of three groups — a connection that is not being made, a filing system that has come apart, or hardware that is failing — and the three groups want three completely different responses. Almost everything people try first is a guess. The sixty seconds is not.
One of those observations outranks the rest, so it comes first and plainly. A drive that clicks, ticks, beeps, buzzes, or spins up and stops and spins up again has broken something mechanical, either heads that have stopped reading or a motor under strain. Every further minute of power drags those heads across the surfaces your files are written on, and the damage adds up. Pull the plug, leave it out, and go straight to the last section of this page. Everything written between here and there assumes a drive that is quiet, and no amount of persistence changes that.
Take the cheap causes in order of cost. Start with the lead, since the cables bundled with portable drives are built to a budget and the USB-C ones give up far more often than anybody expects. Then the port. Plug straight into the computer and steer clear of hubs, monitors, docking stations and the sockets on the front of a tower, all of which are less dependable than the ones on the back. Then a second computer, if the building has one. Mains-powered desktop units such as a WD My Book, a LaCie d2 or a Seagate Expansion Desktop deserve one extra thought: where there is no light, no spin and no sound at all, the little plug-top power supply has usually failed long before the disk it feeds.
On Windows, the truthful picture of what is plugged in sits in Disk Management, reached by right-clicking the Start button. A disk that appears there but not in File Explorer has often just lost its drive letter, and handing one back does no damage. The thing to watch for is a disk marked RAW or unallocated, or an offer to initialise it. Read that as the drive's master index having broken up, not as an empty disk. Your files are nearly always intact underneath, and every repair Windows puts in front of you at that point, initialise very much included, lays new structures over the ones an engineer would otherwise rebuild from. Decline all of them, every time it asks.
On a Mac, the same job is done in Disk Utility with Show All Devices ticked under the View menu. A greyed-out volume sitting under a device that is otherwise present is a common sight and frequently recoverable in full. Two buttons deserve caution. Erase means precisely what it says. First Aid, aimed at a disk that has begun making a noise it did not make before, loads tired mechanics hard at exactly the wrong moment. While the window is open, rule out the dullest possibility of the lot: Windows formatting will not mount cleanly on macOS, and Apple formatting is unreadable to Windows without help. A good number of drives written off as dead are only plugged into the wrong operating system.
The case and the disk inside it are two things that fail separately. Nearly every portable drive puts a bridge board between the USB-C or Thunderbolt socket and the disk's own language, and that board is a common point of failure in its own right. The symptom is distinctive: a light, a faint spin, and nothing at all on screen, with no cable in the world able to talk it round. On the bench the disk is wired up directly and the bridge is left out of the circuit altogether, so it reads as though it had never been in a case at all. It is why a drive that looks completely dead on a kitchen table is often a straightforward job.
That is not an argument for taking the case apart hopefully. Several ranges — most current WD portables, a number of Seagate and LaCie rugged models — encrypt everything in the enclosure electronics, so a bare disk pulled out of the shell reads as noise anywhere else, because the key lived on the board you have just dropped in the bin. Send the whole unit and let it be separated properly. And retire the replug ritual while you are at it. A drive that takes five goes to appear this week and fifteen next week is not being temperamental. It is counting down, and every mount that does succeed brings the last one closer. Those attempts are better spent copying files off than proving a diagnosis you already have.
Merseyside adds one wrinkle worth naming. Salt in the air along the coast at Crosby, Formby and Southport, and the steady damp of a Victorian cellar or an unheated warehouse studio in the Baltic Triangle, work on contacts and board components over years rather than weeks. When it finally goes, the drive usually will not power up at all rather than clicking. That reads as bad news and mostly is not: corrosion eats electronics and leaves magnetism alone, so photographs and project files normally sit intact behind a board that has quietly rotted. That is a board repair, not a write-off.
Four things mark the end of safe DIY. A noise the drive did not make before, particularly after a knock. A RAW disk carrying anything you would mind losing. A drive detected less often with every passing week. Or a recovery program that has run all night and produced nothing that will open. Past any of those the sensible move is a dull one. Lift the bare drive out if it comes away without force, pack it so it cannot move, and post it tracked and insured to the lab at Peter House, Oxford Street, Manchester, about 35 miles along the M62. No collection service operates anywhere on this network, so it is a single parcel and no waiting on a driver. Inside 2 working days of it arriving you get the fault named, an honest view of what will come back, and one written figure, £300 + VAT for any single hard drive or SSD with NVMe included, which you are perfectly free to turn down.
If it is making a noise, it gets no more attempts. No sound a hard drive makes ever improves with use, and heads that have stopped reading are scoring the surfaces your files live on. Pulling the plug once and leaving it out has saved more data than every recovery program ever written.
Free diagnostic within 2 working days of arrival, one fixed written quote, no fix no fee on logical faults. Cards £250 + VAT, any one drive or SSD £300 + VAT.