Why SD cards corrupt files
No scaremongering: SD cards are reliable, and most of them will outlive the camera. When they do corrupt files, it's for mundane, mechanical reasons. Flash memory wears out a little with every write, and a card near the end of its life starts returning bytes that don't match what was stored. Interrupted writes are the bigger everyday risk: a card that loses power or gets yanked mid-write can be left with a half-written file, or worse, a half-updated allocation table, which is how one careless pull corrupts files you weren't even touching. And the card's built-in controller (a tiny computer managing the flash) quietly reorganizes data in the background; cheap or counterfeit controllers cut corners exactly where it hurts.
The good news follows directly from those causes: corruption happens at predictable moments (writing, ejecting, formatting, filling), and habits that respect those moments prevent nearly all of it.
The seven habits
1. Format in the camera, not on the computer
Formatting in-camera gives the card exactly the filesystem layout the camera's firmware expects, which is the standing advice from camera makers themselves, GoPro included. A card formatted by a computer can carry the wrong filesystem variant or leftover folder structures that confuse the camera at the worst moment. Make in-camera formatting part of the rhythm: back up the shoot, verify the backup, format in the camera. A freshly formatted card also sidesteps the slow accumulation of filesystem clutter that comes from deleting files one by one.
2. Never pull the card while the light is blinking
The access light is not decoration; it means the camera is writing. Cameras buffer: the light often keeps flashing seconds after you stopped recording, while the buffer drains to the card. Pulling the card mid-write is the single most direct way to corrupt not just the current clip but the card's allocation table. Wait for the light to go dark, power the camera off, then open the card door. Same rule for batteries: a battery pulled (or dying) during a write is the same interruption with the same result.
3. Eject properly, every time
On the computer side, "safely remove" isn't superstition. Operating systems delay writes for speed: files that look copied may still be partly in RAM, waiting to be flushed to the card. Ejecting forces the flush and detaches the card cleanly; yanking the reader gambles that every write already landed. The habit costs two seconds; losing it costs the one transfer where the gamble fails.
4. Don't shoot on a full card
A card at 98% is an invitation to trouble. The camera fights for the last free blocks while recording, the controller shuffles data harder, and if the card fills mid-clip the camera has to close the file in a hurry. Video files finalized in a panic (or not at all) are a classic corruption source, especially at high bitrates. Leave real headroom, and treat "card full" as something that should never happen mid-recording: swap cards at the break, not when the counter hits zero.
5. Retire cards on a schedule
Cards are consumables. Flash cells have a finite number of write cycles, and a card that has recorded daily for two years has earned retirement, while it still works. Rotate honestly: label cards with their purchase date, cycle through them evenly instead of favoring one, and demote aging cards to low-stakes duty before they fail on something that matters. And retire on evidence: a card that corrupted files once, through no fault of your handling, will do it again.
6. Buy from real channels, and test new cards
Counterfeit SD cards are a genuine industry, and marketplace listings with too-good pricing are their storefront. A fake reports 256 GB, contains maybe 32, and silently wrecks everything written past the real capacity, which means it passes a quick try-out and fails on your longest shoot. Buy from manufacturers' listed retailers, and test every new card once with a capacity checker (F3 on Mac/Linux, H2testw on Windows) before it goes in the bag. Twenty minutes of testing versus a wedding on a card that lies about its size.
7. One card, one camera
A card that lives in a single camera gets formatted by one firmware and written by one device, which is the simplest, safest life a card can have. Shuffling a card between a drone, an action cam, and a laptop multiplies the chances that one device leaves the filesystem in a state another mishandles. Dedicate cards, label them, and move footage by copying to a computer, not by treating the card as a shared shuttle drive.
If it already happened
Checklist or not, sometimes you're holding a card with a problem. Sort it into one of two bins, because the fix is different:
The card reads fine, but files won't open. This is file damage, not card damage, so it's a repair job. Copy everything off the card, then repair the copies: videos (including GoPro and DJI drone footage) and photos. Keep the originals untouched until you've confirmed the repairs.
The card won't mount, or files have disappeared. That's a recovery problem, and it comes first: recovery software has to get the data back before there's anything to repair. Stop writing to the card immediately, because every new write may overwrite what you're trying to rescue. Expect some recovered files to need repair afterward; that's normal, and here's why.
The printable checklist
The seven habits, condensed to one sheet for the camera bag. Printing this page outputs just the checklist, on a single page.
SD card field checklist
intactfile.com/blog/avoid-corrupting-files-sd-cards
Before the shoot
- Card was formatted in this camera after the last confirmed backup
- Card has real headroom (swap planned before it fills)
- New cards came from a real retailer and passed a capacity test (F3 / H2testw)
- Spare formatted card in the bag
During
- Card never leaves the camera while the access light is on or blinking
- Camera powered off before the card door opens
- Batteries swapped early, never dead mid-write
- Card stays with its one camera
After
- Footage copied to computer; copies spot-checked (files open)
- Card ejected properly before the reader is unplugged
- Backup verified, then card formatted in-camera, not by picking off files one by one
- Cards rotated evenly; heavy-use cards retired on schedule or after any error
If something breaks
- Card readable, files won't open → repair the files: intactfile.com/repair-video
- Card unreadable or files missing → stop writing to it; recovery first, repair after
FAQ
Why does my SD card keep corrupting files?
Repeated corruption on one card is a pattern, not bad luck. The usual suspects, in order: the card is being removed or the reader unplugged before writes finish; the card is counterfeit and wraps around once you pass its real capacity; the card is worn out from years of use; or the card is being shuffled between devices that disagree about its filesystem. If a second, known-good card behaves fine in the same camera and workflow, retire the first one. If every card corrupts in one camera, suspect the camera or its reader.
Should I format my SD card in the camera or on the computer?
In the camera, every time. The camera formats the card exactly the way its own firmware expects: right filesystem variant, right allocation size, right folder structure. Computer formatting tools offer options the camera may not handle well, and a card formatted on a computer can behave oddly until the camera reformats it anyway. Camera makers, including GoPro, recommend in-camera formatting for exactly this reason. Format after every confirmed backup, not just when the card fills up.
How do I know if my SD card is fake?
Test it, don't eyeball it: good fakes copy the packaging perfectly. A counterfeit card reports a large capacity but physically contains less flash; it works fine until your data crosses the real limit, then silently destroys whatever lands past it. Free testers (F3 on Mac/Linux, H2testw on Windows) fill the card with test data and read it back, exposing the real capacity in one pass. Run the test once when the card is new, before it ever touches a shoot.
How often should I replace SD cards?
Flash memory wears out with writes, so it depends on duty cycle. A card that records video every working day is doing vastly more writes than a weekend stills card, so treat heavily used cards as consumables and rotate them out after a year or two of professional use. Replace any card immediately after its first unexplained error, a corrupted file that wasn't your handling, or any physical damage. Cards are the cheapest component in your kit; the footage on them is the most expensive.
Can files on a corrupted SD card be recovered?
Usually something can be, but be precise about which problem you have. If the card mounts and you can copy files off it but some won't open, that's a repair job: the files need their structure rebuilt. If the card won't mount or files have vanished, that's a recovery job: specialized software (or a lab, for physical damage) must find the data first. Recovery often returns files that still won't open, and those then need repair. See why recovered files won't open.
Related guide: recovered files won't open? Why data recovery is only half the job.