Corruption never comes from nowhere. An SD card that suddenly demands formatting, shows empty folders or serves up gibberish filenames got there by one of a handful of well-worn roads — and knowing which one changes both the rescue and whether the card deserves a second life. Causes first, then the rescue, then the repair.
Pulled mid-write. Shuffled between devices. Counterfeit capacity. Worn-out flash. Each leaves its own fingerprint — and none of them, caught early, has to cost you the photos.
Interrupted writes lead the table. A card pulled while the camera’s buffer is still flushing, a battery dying mid-burst, a phone rebooting during a save — the file system’s bookkeeping is caught mid-sentence, and next insertion the device can’t parse it. Device-hopping is subtler: camera to phone to laptop to smart TV, each with its own ideas about how the file system should look, each ‘helpfully’ writing thumbnails and indexes until the structures disagree with themselves. Counterfeit capacity is the cruellest — a small chip reprogrammed to claim 256 GB works perfectly until you write past its real size, then silently overwrites earlier photos and corrupts wholesale; suspiciously cheap cards from marketplace sellers are the classic source. And plain wear: flash memory has a finite write life, budget cards use the cheapest grades, and a card that’s been the workhorse for years eventually starts mis-remembering. Different roads — but they all arrive at the same place, which is why the rescue is universal.
Stop using the card the moment corruption shows — every further write happens on top of your photos’ last known addresses. Connect it to a computer through a card reader (the camera-as-cable route is slower and flakier), decline every prompt the operating system offers — format, scan-and-fix, initialise, all of them write — and run PhotoRec: free, read-only, and built to carve photos and video straight out of the flash whether the file system makes sense or not. Point its output at a folder on the computer, never at the card, and judge the harvest by opening files, largest first. Ten minutes of discipline recovers the overwhelming majority of corrupt-card cases without spending a pound.
The exception that skips the ten minutes: a card that isn’t detected at all, heats up, or physically rattles. That’s hardware — controller failure or worse — and home tools have nothing to grip; monolith-level reads on the bench do. Our memory card recovery service starts with the free diagnostic either way.
With the photos verified safe on the computer, the card can be dealt with honestly. A full format in the device it will live in rebuilds every structure and returns most cards to service. But apply the two-strikes rule: corruption that arrived without an obvious cause — no yanked card, no dead battery — is usually the flash itself deteriorating, and a card that corrupts twice has told you its plans. Cards cost pounds; reshooting a christening costs the impossible. Retire suspects, buy branded from reputable sellers, format in-device rather than in Windows, and treat every card as a courier rather than an archive — photos should move off it within days. Formatted the card before reading this and then remembered what was on it? Same carving method, dedicated page: formatted media recovery.
No — and intermittent behaviour is the opposite of healing. A card that reads on the third try, or works in the camera but not the laptop, is a card whose controller or contacts are deteriorating between attempts. Each retry is another chance for a half-write to make the corruption worse. Treat the first corruption as the card’s resignation letter: get the photos off, then retire it.
Repeat corruption almost always has a cause you can name. The usual four: the card shuttles between devices that each treat its file system differently; it gets pulled or the battery dies mid-write; it’s a counterfeit whose real capacity is a fraction of the label, corrupting everything written past the true limit; or the flash is simply worn out. Genuine branded cards, formatted in the device they live in, removed only when writing has finished, almost never make a habit of it.
Not while the photos are still on it. CHKDSK repairs file systems by writing corrections — and its infamous habit of converting damaged files into useless FILE0000.CHK fragments has cost people entire shoots. The safe order is absolute: carve the photos off first with a read-only tool, and let CHKDSK or a format rebuild the card afterwards, when there’s nothing left to lose.
Free 48-hour diagnostic at the Bristol lab — an honest read of what happened to the card and whether DIY carving is safe, before anything is risked.