Everyone's immediate reaction is to grab for an additional cable. Leave that for sixty seconds and look at it instead. Is light coming from it? Are there any slight vibrations in the case, which would indicate the platters are spinning? Is it making any noises that it wasn't making a month ago? The combination of these three checks will narrow almost all lost drives down to one of three possible faults (a connection problem, a corrupted file system, or faulty hardware) and each of those should be handled differently. No amount of guessing will help you. Taking a minute to observe your hard drive will go a very long way.
One of these three trumps all the others, so deal with it now. A clicking, ticking, beeping, buzzing, or spinning up then collapsing and starting over is a mechanical failure: either a head can't read the data on the disk, or a motor is having trouble turning. The longer the minutes go by and you continue running the dead heads across where your files are stored, the greater damage occurs. Shut off the power source. Remove from use. Skip to the final section. Once a drive has started producing noise, none of what lies in-between here will apply, and repeating the attempt will make no difference.
Begin with the lead, because the cables that come with portable hard disks are created on a budget, and the USB-C ones are more prone to fail than many people believe. Next is the socket: simply connect the cable directly to the machine, avoiding ports that sit in hubs, docks or monitors (and those ports on the front of a tower), as these will be less reliable than any port located in the rear of your tower. If you have access to a second computer, try using it too. Mains-powered desktop units (a WD My Book, a LaCie d2, a Seagate desktop Expansion) get an extra suspect for failure. If one of those shows nothing at all, no light, no sound, no sign of spinning, it is usually the little plug-top adaptor that has failed rather than the disk inside.
On Windows, you get the truthful picture in Disk Management, which you open by right-clicking the Start button. There are two scenarios to look for. If the disk shows up as having an existing (healthy) partition but no letter, just assign it a drive letter. This will not harm your data and frequently sorts it outright. If instead the partition reads RAW or unallocated space, or if Windows prompts you for permission to initialise the disk, then the map has been lost. However, all of your files remain intact. Any options provided here (including initialise), will lay new structure on top of the original structure. The original structure is what a recovery can read. Decline them all and leave the disk alone.
On a Mac, the equivalent is Disk Utility. Set your "View" option to "Show All Devices". This will allow the disk (the entire drive) to be viewed as opposed to viewing only its individual partitions or volumes. If the volume underneath is greyed out but the device is still visible, this is perfectly normal, and the volume often recovers in full. There are two buttons in Disk Utility that deserve respect. The first is the "Erase" button, and erase means erase. The second is the "First Aid" button. It runs through a series of checks and repairs on the selected disk, which works a struggling mechanism hard for a long spell, so if you have a disk making strange noises, it is precisely the wrong treatment. While using Disk Utility, one possible item to remove from consideration: media formatted by Windows may not mount properly under macOS, and media formatted by Apple may not show up when viewed under Windows. Some dead drives are simply plugged into the wrong operating system.
Drive failures up here have patterns, and when those patterns emerge they tell you what you are dealing with. First, there's salt air. If a drive has been stored in a bag on a boat, in a harbour office or in a van travelling between Peterhead and Fraserburgh, then corrosion will likely start at the electronics before the hard drive fails otherwise. The symptom of this failure is a drive that used to work and now does not show any lights. This is typically due to a circuit board (board) fault. Board faults can frequently be recovered fully, because the platters never knew anything had happened.
The second is cold. In an unheated garage or shed where the unit has sat through a hard winter, when it is brought back into your house and immediately plugged in, there will be condensation building up inside the precision mechanisms, which are built to exacting tolerances of mere nanometres. Allow it to come to room temperature prior to powering it up. The third is vibration, which is the offshore and site-work problem: equipment that is moved from one location to another constantly may develop mechanical problems months before it exhibits symptoms of those issues, and the first symptom is often a drive that mounts much slower than normal, or mounts one day but not the next. An intermittent fault does not mean that the fault is mild. Intermittent means the fault is simply announcing its intent. Copy all data from the failing unit on the first day it starts acting intermittently, as the second failure will normally be a permanent fault.
There is a clear line. Checking your cables, ports and another machine, and looking at Disk Management or Disk Utility, cannot make anything worse. Beyond this point you find the methods that could potentially cause harm to your data: chkdsk/scan-and-fix on a corrupted volume, First Aid on a noisy disk, initialising/re-formatting, and running a variety of 'data recovery' programs that can run continuously against faulty hardware for up to six hours. While there are some legitimate uses for consumer data recovery applications (a healthy hard disk from which you accidentally deleted files) the danger exists with them when used anywhere else, as they continue to put additional strain on an already failing piece of hardware at the exact time it needs to be turned off.
When your drive gets to us, it will be connected to a hardware write blocker, therefore it will always be imaged on a read-only basis and nothing is written back to your media. Once the image has been taken off the drive, the files can be re-constructed. Diagnosis takes no more than 2 working days after receipt of the parcel and there is no cost for diagnosis. After diagnosis, you receive a single fixed written price. For logical errors, in most cases you only pay if we recover your data. For mechanical, electrical, water and fire damage, 50% payment is due prior to being placed on the bench, and the remaining amount is only owed if we recover your data. Please contact us before sending your drive to obtain a quote either via phone or using the free online diagnostic tool. You should then send the complete drive in its enclosure, with its own cable and power supply: post it tracked and insured, use a courier you book yourself, or drop off your drive at our Edinburgh counter (Monday to Friday, 9am to 5:30pm, no appointment needed). We never pick anything up from customers. Ring 0800 689 0668 before you pack it if you are unsure.
There should be no additional recovery efforts if there is audible activity. Nothing a hard drive does that you can hear is improved by use, and heads that stop reading will continue to damage the surface your files are stored on. Leaving it plugged in one evening has turned many complete recoveries into partial recoveries. Shut it down first, get a quote before packaging it up, then let someone properly look at it.
The diagnosis is free and takes 2 working days once your disk arrives at our premises. The figure quoted is fixed and given to you in writing, and on logical work, in most cases you only pay if we recover your data. Begin online today or call us.