The wording is the trouble. A card that has lost its index produces a message about formatting, and formatting sounds like the only door out of the room, so people click it. Nine times out of ten the photographs are precisely where the camera left them at that moment, and the next thirty seconds decide how many of them ever come home.
Three things are stacked inside that little piece of plastic. At the bottom is the warehouse: flash memory, where each photograph exists as trapped charge in a cell. Above it sits the foreman, a small processor called the controller, which decides where things physically go, spreads writing about so no one area wears out early, and quietly retires cells that have started to fail. On top of both sits the inventory — a file system, FAT32 on smaller cards and exFAT above 32GB — which does nothing except list each file with its name, its size and where it starts.
The sizes are worth dwelling on. That inventory occupies a few hundred kilobytes and describes tens of gigabytes of pictures. It is also the only part under constant revision: it gets rewritten every time you save a frame and every time you delete one, while the photographs themselves are written once and never touched again. Wear follows use, so the inventory is what tears.
It tears in ordinary circumstances rather than dramatic ones. A card pulled while the access light is still on. A battery that goes flat in the middle of a burst. Contacts with a morning's damp on them dropping the connection at the wrong instant. A card yanked out of a reader without being ejected. In every case the pictures are untouched and the one-page list describing them is not.
Windows says the card needs to be formatted before you can use it. Translated honestly, that reads: I looked for an inventory I recognise, I did not find one, and I am offering to write a blank one for you. It is a statement about a few hundred kilobytes at the front of the card. It is not a statement about your photographs, and the machine has not looked at them.
macOS phrases the same discovery differently — the disk is not readable by this computer — with buttons offering to initialise or eject. The camera version is blunter still: card error, or a folder that shows no images. Three different wordings, one underlying event, and none of them means what people take it to mean.
Once that is clear the rest of this page follows naturally. The job is to get a copy of the shelves without ever letting anything write a new inventory on top of the old one.
Say no to the format. Accepting it lays a fresh empty index over the damaged one, which closes the quick route home and leaves only the slow one. It is not the end of the world — a quick format leaves the picture data where it was — but it turns a job with filenames into a job without them.
Say no to the offer to scan and fix, too. That is the same trap wearing a friendlier coat: tools of that kind exist to leave a file system internally consistent rather than complete, and consistency gets achieved by discarding whatever will not reconcile. The long version of that argument is on what CHKDSK does to a damaged volume, and every word of it applies to cards.
And do not put the card back in the camera to find out whether it still works. Whatever you photograph goes into blocks the controller currently regards as spare, and because wear levelling picks them you have no say at all in where that lands physically. A single test frame can come down on top of a wedding. None of these three moves can be undone afterwards, by anyone, for any money, which is why the right answer here is the one that feels like surrender. Take the card out, put it where nobody will pick it up, and leave it. Cards do not deteriorate in drawers.
None of these writes anything, and between them they account for a fair share of the calls, so they are worth two minutes before assuming the worst.
The lock tab. A full-size SD card has a little slider along one edge, and the rest of a camera bag spends its life knocking that slider downwards. Locked, a card reads erratically or refuses outright. The contacts. Finger grease, dust and what a damp morning leaves behind all get between the metal and the reader, and a dry cloth sorts that out at no cost.
The reader. It causes far more trouble than it ever gets blamed for. Cheap adapters lose the spring in their contacts somewhere in the first few hundred insertions, and a laptop slot that has swallowed thousands of cards is no better off. Both throw read errors on media that a decent powered reader takes without complaint, so try the card somewhere else before concluding anything about the card itself.
A card that was never what the label claimed. Cards bought very cheaply from online marketplaces are sometimes reprogrammed to advertise a capacity the memory does not have. They behave impeccably until the real capacity runs out, at which point later files quietly land on top of earlier ones. If the trouble started exactly when the card filled up, that is the likeliest explanation, and nothing recovers data that was never written anywhere in the first place.
Four symptoms belong to one family. A format that gives up halfway. A capacity reported as a small fraction of the real one. A card that says it is 0MB. A card that has locked itself read-only for good. Every one of those is the foreman talking, not the warehouse burning down.
Controllers are designed to fall back into a locked read-only state as soon as their internal error and wear counters pass a set point, on the view that keeping what is already stored beats risking further writes. They can also lose the tables translating addresses into locations if power disappears at precisely the wrong microsecond, after which the chip has no idea where anything lives. Either way the middle layer has stopped behaving to a rule, and no utility you can download will talk its way past it. Forums recommend low-level formatting tools for exactly these symptoms, and they are a dependable method of finishing off a card that still holds something worth having.
So the way through goes around the foreman rather than arguing with him. While the controller still holds a conversation, a write-blocked image is taken in repeated slow passes that shrug at errors rather than halting on them. Once it has gone quiet for good, a programmer addresses the memory packages directly, and that is where the real labour starts, because nothing resembling a photograph falls out of raw flash. Data was interleaved over several dies and planes on the way in, scrambled to a pattern, and wrapped in a correction scheme; all three have to be deduced before one frame appears. How hard that gets depends on how the card was built. Full-size SD normally houses memory and controller as separate parts. Most microSD is moulded as one solid body, so contact has to be made at test pads on the outside, which counts as chip level work — one of the four published exclusions from no fix, no fee, taking half the figure in advance. It is also the reason a cracked card wants leaving strictly alone: one more flex and the bond wires have gone. SD and memory card recovery goes into the construction properly.
Your card is read, and nothing else is done to it. A complete sector-by-sector copy comes off first, behind a write blocker, and every decision afterwards is taken against that copy. Working in that order has two useful consequences: a card already on its way out is never driven further downhill by the recovery itself, and nothing that goes wrong at this end can reach the original.
Where enough of the inventory has survived inside the copy, it is patched up and the folders return in the shape the camera left them, filenames intact. Where it has not, the pictures get found by what they are made of. Every JPEG opens on a distinctive run of bytes, and so does every raw file worth shooting — CR3, NEF, ARW and the rest — so frames can be pulled out of unallocated space when no index exists anywhere. That route is paid for in names: files found by content come back numbered instead of titled, which bothers some people and not others.
Nothing is described as recovered until it has passed two checks. Stills are opened and drawn on a screen rather than counted in a results pane, since a name in a list and a picture that renders are separate claims. Footage is looked at harder still: a long clip lives in fragments spread right across the card, so anything written later is likely to spoil a passage in the middle of it rather than shortening it neatly at the end. Which is one more reason to keep a misbehaving card out of the camera. If the format has already been accepted, recovering a formatted SD card covers what survives.
The cards reaching this bench from Coventry and Warwickshire follow a steady pattern. Wedding and event photographers working across the county. Tourism and heritage shoots around Stratford. Media students at Coventry and Warwick with a term of field recordings on one card and nothing anywhere else. Dashcams off the M6 and the M69 after an incident nobody expected to need footage of. Drone cards from site surveys over the distribution parks. These are cards that live in bags, get swapped over with cold fingers on wet mornings, pick up damp that never entirely leaves them, and go in and out of readers several thousand times more than the contacts were ever specified for.
Packing one takes two minutes. Sandwich the card between folded pieces of stiff cardboard so it cannot flex, put that inside a padded envelope, and send it tracked to Oxford Data Recovery, John Eccles House, Oxford Science Park, Robert Robinson Avenue, Littlemore, Oxford OX4 4GP. Postage on something that light is pennies. Driving is an option too — about fifty-five miles down the M40 from Coventry, an hour or so — and the reception desk signs devices in Mon–Fri 9:00am–5:30pm. There is no Coventry counter and nobody collects.
Cards, sticks and pen drives all sit in one band at £250 + VAT. Nothing is charged for the assessment, which closes 2 working days from booking in and ends in a written figure that holds; from approval, most of this work goes back out within 2 to 4 working days. Anything needing the memory read directly off the silicon is chip level work — one of the four published exclusions — and half the figure goes in first. Alongside this page sit memory card recovery, recovering a formatted SD card, USB memory stick recovery and data recovery cost. The freephone is 0800 689 0668.
A few hundred kilobytes tore, and they were describing forty gigabytes of pictures. Nothing you do now will bring back a frame once something has been written over it, and nothing you leave undone will make the card any worse while it sits in a drawer. Doing nothing is a real decision here, and it is usually the right one.
Oxford charges nothing to examine it, and that closes 2 working days from the moment it is booked in. Whatever figure comes out of it is written down and stays there: £250 + VAT a card or stick, £300 + VAT one drive or SSD.