External hard drive not showing up? Work the checklist, not your luck

Thirty seconds of looking before any clicking around

The most useful diagnostic tool you own is thirty seconds of patience. Connect the drive, then do nothing: watch whether the LED lights, rest a finger on the casing to feel for the faint vibration of spinning platters, and listen closely. What you notice sorts the problem into one of three boxes (a connection issue that costs pennies, a corrupted file system that needs care, or failing hardware that needs a lab), and everything sensible you do next depends on which box you're in.

One observation overrides all the others. A drive that clicks, chirps, beeps, or spins up then dies again in a loop has a mechanical problem: failing read/write heads or a stuck spindle motor, very often after a knock or a fall. Powering it again grinds delicate heads against the surfaces that hold your files. Unplug it, keep it flat and still, and skip ahead to the final section.

Checks that carry no risk at all

Start where failures are cheapest. Swap in another USB lead (the ones boxed with portable drives are famously flimsy), then move to a socket on the computer itself rather than a hub, monitor or front panel, then borrow a second machine if there's one about. A desktop drive with its own mains adapter deserves equal suspicion of that adapter: no spin at all often means a dead power brick rather than a dead disk.

On Windows, the honest picture is in Disk Management, which you reach by right-clicking Start. A disk listed there but missing from File Explorer may simply need a letter, and assigning one through 'Change Drive Letter and Paths' touches nothing important. The dangerous branch is different: a disk showing as RAW or 'unallocated', or a prompt to initialise, means the file system has broken. In most cases the files are still intact behind that broken index, and every rescue Windows offers (initialise, format, repair) writes over the structures an engineer needs. Refuse all of them.

Mac owners should open Disk Utility and choose Show All Devices from the View menu. Hardware that appears with a volume that won't mount is a common sight; the traps are Erase, which does exactly what it says, and First Aid on any drive making new noises, since repair passes push failing mechanics hard. Rule out one false alarm too: a disk formatted NTFS for Windows won't behave properly on macOS, and an APFS disk means nothing to Windows. The data is fine; it's just sitting on the wrong platform's desk.

Seagate and WD: the two quirks that fool everyone

Seagate portables show a particular pattern: the LED is on, it sounds normal, and it appears nowhere. Nine times out of ten that's the USB bridge board or its firmware playing up rather than the disk, and a new cable won't cure it, though bench equipment reads straight past it. WD's My Passport and Elements ranges hide a different trap: the bridge encrypts on the fly, so taking the disk out of its case and connecting it bare gets you ciphertext, not files. Recovery has to go through that original board, or rebuild what it was doing.

Whatever brand you own, stop the replugging ritual. A drive that mounts on the fifth attempt today and the fifteenth tomorrow is failing on a schedule, and each retry burns some of the remaining life you'd rather spend on the recovery itself.

The symptoms that end the DIY phase

Draw the line at any of these: noises after a drop; a RAW disk holding files you can't lose; detection that keeps getting rarer; a recovery app that has scanned all night for nothing. Beyond that line you're gambling the data to avoid the cost of finding out, and finding out here is free.

First, get a quote, either by phone or with the free online diagnostic. Then pack the drive carefully, still in its enclosure with its cable and power supply, and post it to us tracked and insured. Within 2 working days of it reaching the bench you'll have a diagnosis, an honest list of what's recoverable and one fixed figure to say yes or no to. The full service is set out on the external hard drive recovery page; to make a start, open the free online diagnostic and tell us what happened.