SD cards · triage guide

Corrupted SD card: fix it, or recover from it?

‘Card error’, ‘needs formatting’, files turned to gibberish, folders showing empty — corruption wears many faces, and the right move depends on which one you’re looking at. This is the triage we run, written down — including the order of operations that protects the photos while you fix the card.

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// the golden rule

Fixing the card kills the files.

Nearly everything that repairs a corrupted card works by rewriting its structures — the same structures your photos hide behind. Recover first. Repair after. Never the other way round.

Asks to format
Decline — carve first
Shows RAW / 0 GB
Index gone — carve
Not detected
Hardware — lab
Files garbled
Stop writing now
// triage

Read the symptom, pick the lane.

Four presentations cover almost every corrupted card we see.

‘You need to format this card.’ The friendliest-looking and most dangerous prompt. The card’s file system has stopped making sense to the device, and the device is offering to blank it. Decline, connect the card to a computer through a reader, and carve the photos off with PhotoRec — corruption breaks the index, and carving never needed the index in the first place.

Shows as RAW, 0 bytes, or a wrong size. Same disease, different rash: the structures describing the card are damaged while the photo data behind them usually survives. Carve first; format later. If Windows nags you to ‘scan and fix’, decline that too — repair tools write.

Files present but broken — photos that open half-grey, videos that stop mid-play, filenames in symbols. This is corruption caught mid-act, often from a card pulled during a write or a counterfeit card running out of real capacity. Copy off everything that opens, carve for the rest, and retire the card.

Not detected at all — nothing in the camera, nothing in the reader, no sound from Windows. That’s not corruption; it’s failure of the card’s controller or physical damage, and no software can address hardware. Monolith cards like these are read at chip level on the bench — the core of our memory card recovery work.

// afterwards

Once the photos are safe, then fix the card.

With the files recovered and verified on your computer — open a sample, don’t take the file count’s word for it — the actual repair is anticlimactic: a full format in the camera it will live in, which rebuilds every structure fresh. If a formatted card corrupts again within weeks, stop giving it chances; flash memory fails progressively, and the second corruption is rarely the last. Two habits prevent most repeat visits: never pull a card while the device is writing, and treat cards as transport rather than archives — photos should live on the card for days, not months. Formatted it already and then remembered what was on it? Different problem, same physics — our formatted media recovery service handles exactly that, provided the card hasn’t been refilled since.

// mid-shoot

‘Card error’ in the middle of the job.

The cruellest timing is mid-shoot: the camera flashes a card error with the event still happening around you. The field protocol, in order: don’t format from the camera menu, however helpfully it offers; swap to a spare card and keep shooting — the rescue can wait, the ceremony can’t; power the camera off before removing the suspect card, then write-lock it (the little side switch on full-size SD) and pocket it separately from the working spares. Everything on it is now frozen exactly as the error left it — the ideal starting state for the carving rescue on this page, or for the bench if the card has gone properly silent. And afterwards, one habit upgrade: cards fail mid-shoot far more often at the end of long service lives, so professionals cycle cards out of front-line duty long before they die of old age.

// questions

Asked before you ask, answered.

Order is everything: recover first, repair second. Most ‘fixes’ — formatting, error-checking tools, letting the camera reinitialise the card — work by rewriting the card’s structures, which is exactly where your photos’ last traces live. Image or carve the photos off first with a tool like PhotoRec; once they’re safe, format the card freely and it will usually work again.

Because the card’s table of contents no longer makes sense to it — usually after a card was pulled mid-write, used across two devices, or has a controller starting to fail. The format prompt is the device offering to write a blank new index. The photos behind the unreadable index are typically still there, which is precisely why you should decline.

Recover the contents, then bin it — that’s our honest advice in most cases. Corruption that arrives out of nowhere is often the first symptom of failing flash memory or a tired controller, and a card that’s lied to you once doesn’t deserve your wedding shoot. Cards are cheap; the photos on them aren’t.

If it’s new, from a marketplace bargain, and corrupted once you’d filled it past a certain point — very possibly. Counterfeits carry small flash reprogrammed to claim big capacities; everything written past the true size silently destroys earlier files. Free capacity-testing tools verify a card’s honest size in an hour. Genuine cards from reputable sellers make corruption an event; fakes make it a schedule.

// card being difficult?

Don’t format your way out of photos.

Free diagnostic at our Belfast lab — we’ll read the card’s symptoms, tell you honestly whether DIY carving is safe, and quote in writing before any work.

Call us — 028 9002 0144
Mon–Fri · 9am–5:30pm · No fix, no fee
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