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SD card · not reading

SD card not reading?

A card that won’t mount, shows as empty, or isn’t recognised on any device isn’t always dead — and the cause matters, because it decides what you should (and shouldn’t) do next. The reasons range from a faulty reader to a corrupt file system to a counterfeit card. Here’s how to work out which, and how to get your photos off one that’s stopped reading — without making it worse.

Read in a proper reader
Files carved off
From £250 +VAT
// the short version

Not reading ≠ not dead.

Most cards that stop reading do so for a fixable reason — a bad reader, dirty contacts, or a damaged file system — and the data is still there. The trick is to diagnose before you reformat.

Reader
Try another
Contacts
Clean / reseat
Corruption
Carvable
Fake card
Bench job
×Don’t format a card that won’t read — not if the photos matter. A “you need to format this disk” prompt is asking permission to wipe it. Recover the files first, then format. And don’t keep reinserting a failing card into a camera, which can make a marginal fault worse.
// why a card stops reading

A handful of usual causes.

When a card won’t read, it’s almost always one of a few things. The simplest is the reader or slot itself — a worn card reader, a dirty USB port, or a laptop slot that’s stopped making contact. Next is the card’s contacts: bent, worn or grimy pins that stop it seating properly. Then there’s file-system corruption, usually from a write being interrupted — pulling the card out mid-save, or the camera battery dying during a write — which leaves the data intact but the index unreadable. Less often it’s physical damage (a cracked or snapped card), or a counterfeit “fake capacity” card that was doomed to fail once it filled up. Each points to a different next step.

// quick checks first

Rule out the easy ones.

Two minutes here can save a recovery bill.

Before assuming the worst, try the card in a different reader and a different computer — use a proper card reader rather than the camera, since camera slots and cables are a common point of failure. Have a careful look at the gold contacts and gently reseat the card; a wipe with a dry cloth can fix a grimy connection. If it mounts on another machine, don’t celebrate and carry on — copy the important files off immediately, because a card that reads intermittently is warning you. If it still won’t show up anywhere, the problem is the card, and it’s time to think about recovery rather than more attempts.

// if it’s corrupt or asks to format

Read it, don’t rewrite it.

A card that mounts but shows as empty, reports the wrong size, or demands formatting has almost certainly suffered file-system corruption — and crucially, the photos are usually still on it. The right move is to read the card at a low level in a reader and carve the files out past the broken file system, saving them somewhere else entirely. Windows’ chkdsk can sometimes repair the structure, but it can also overwrite data while it does, so it’s only safe once the files are already copied off — the same principle behind recovering any formatted or reformatted media. If in doubt, don’t experiment on the only copy; get a diagnostic.

// physical or fake cards

When it’s bench work.

If the card is cracked, snapped, or has been through the wash, or if it turns out to be a counterfeit that reported far more capacity than it really had, that’s a job for the bench rather than a card reader. Physically damaged cards can often still be read by accessing the memory directly, and counterfeit cards can usually be recovered up to their real capacity. Either way it starts with a free diagnostic, and a single memory card is from £250 +VAT. If the shots on it are irreplaceable, that’s far better than another round of reinserting it and hoping.

// questions

Your questions, answered.

Usually one of a few reasons: a faulty card reader or port, dirty or worn contacts, file-system corruption from an interrupted write, physical damage, or a counterfeit fake-capacity card. The first three are often fixable and the data is intact; the last two are bench work. Trying the card in another reader tells you a lot before you go further.

If it mounts on another reader, copy the photos off straight away. If it shows as empty or asks to be formatted, do not format it, the photos are usually still there and can be carved off by reading the card at a low level. If it will not read on any device or is damaged, send it in for a free diagnostic rather than retrying it.

Not if the data matters. A format request is asking to wipe the card, and while formatting may make it usable again, it destroys the photos in the process. Recover the files first, then format. If recovery software cannot see the card, get it diagnosed rather than formatting and hoping.

Not necessarily. A card that is not recognised anywhere may have worn contacts, physical damage, or be a failed counterfeit, and in most of those cases the memory can still be read directly on the bench. It is worth a free diagnostic before writing it off, especially if the photos on it are irreplaceable.

A single memory card is from 250 pounds plus VAT, whether the fault is corruption, physical damage or a fake-capacity card. You get a free diagnostic and a fixed written quote before any chargeable work, and it is all done in-house.

// card won’t read?

Get the photos off it safely.

Don’t reformat and don’t keep reinserting it — send the card in and we will tell you what is recoverable before you spend anything. Free diagnostic, fixed written quote.