Before you touch a single setting, plug the drive in and just watch and listen to it for a couple of minutes. Does the light come on? Rest a finger on the casing — can you feel it spin up? Is it completely silent, or has it started making a sound you have never heard from it before? Those clues matter, because 'not showing up' actually covers three very different faults: a connection problem (cheap to fix), a software problem (fixable with care), and a hardware failure (a job for the lab).
If the drive is clicking, buzzing, beeping or spinning up and down on repeat, stop right here. Those noises are mechanical — usually failed read/write heads or a motor that has seized, and far more likely if the drive has been dropped or knocked. Every extra minute of power risks scoring the platters your data lives on. Pull the plug and skip straight to the final section of this guide.
Swap the USB cable first — the flimsy leads bundled with portable drives fail constantly, and Seagate and WD models are especially prone to it. Next, change the port: plug directly into the machine rather than a hub or the front-panel sockets, and if you can, test the drive on a completely different computer. Desktop drives with their own power brick depend on that brick working — if the disk will not spin at all, try a known-good adapter before you fear the worst.
On Windows, right-click the Start button and open Disk Management. A drive that shows there but not in File Explorer has probably just lost its drive letter — right-click the partition and pick 'Change Drive Letter and Paths' to give it one. If instead it reads as RAW, 'unallocated', or asks to be initialised, the partition or file system has corrupted. Your files are most likely still there, but do NOT initialise, format or accept Windows' offer to 'fix' it — every one of those writes over the exact structures a recovery rebuilds from.
On a Mac, launch Disk Utility and choose View → Show All Devices. If the physical disk appears but its volume will not mount, resist Erase (that wipes it), and think twice before running First Aid on a drive you can hear straining — repair routines force a sick drive to work harder. And a disk that mounts happily on Windows but not on Mac (or the other way round) is normally just formatted for the other platform; the data is fine, so read it on the system it was made on.
If your Seagate drive lights up but appears nowhere, and it is not making any odd noises, the usual suspect is the USB bridge board or its firmware — recoverable, but not with a new cable. And if you are tempted to prise the enclosure open and wire up the bare drive inside, save yourself the effort on most current WD My Passport and Elements units: their USB board encrypts the data in hardware, so the naked drive just reads as nonsense in another caddy. A lab reads it properly by working with or around that original bridge.
Either way, don't keep re-inserting the drive 'just to check whether it comes back'. Detection that grows rarer over a few days is a failure curve, not a mood — each retry is one more rotation of hardware that is already on its way out.
Stop straight away if the drive clicks, beeps or has been dropped; if Windows calls it RAW or uninitialised and the files matter; if detection is intermittent and getting worse; or if you have already let recovery software grind away for hours and turn up nothing. The honest arithmetic at that point is simple: more DIY endangers the data, and finding out exactly what is wrong costs you nothing.
Post the drive to our lab (no cables needed, bubble wrap does the job) and within 48 hours of it arriving you will have the diagnosis, a clear list of what is recoverable and one fixed price — no fix, no fee. There is more on the external hard drive recovery page, or you can begin with the free online diagnostic.
Golden rule: if the data matters and the drive is making any sound it never used to — clicking, buzzing, beeping — cut the power now. Mechanical faults only ever get worse the longer they run.
Free diagnostic, fixed quote, no fix no fee — start now or call the freephone.