SD card error? How to save your photos and video

Memory cards are small, cheap and usually reliable, which is exactly why a failure comes as such a shock. One moment the camera is recording a wedding, a holiday or a day’s site photos; the next it shows “Memory card error”, “Card not formatted” or simply refuses to see the card at all. The good news is that photos and video on a failed SD or microSD card can often still be recovered. The bad news is that the most natural reaction, formatting the card so the camera works again, is the one most likely to make things worse. Here is what the common errors mean and what to do.

Common SD and microSD card errors

• “Memory card error”, “Card cannot be accessed” or “Err 02”-type messages on a camera. The camera cannot read the card’s file system. Causes range from a corrupted directory to a failing controller inside the card.
• “Card not formatted” or “Format this card?” The camera, phone or computer sees the card but not a valid FAT32 or exFAT file system on it.
• “You need to format the disk” on a Windows PC, or the card showing as RAW or 0 bytes.
• Card not detected at all, or detected with the wrong capacity (for example a few megabytes, or a generic name instead of the brand). This usually points to a controller or firmware failure.
• Card is write-protected even though the lock switch is off. Many cards deliberately switch themselves to read-only when the flash memory wears out or the controller detects a fault, to protect what is already stored. Check the slider on full-size SD cards and adapters first, as it is easily knocked.
• Files that are there but will not open, show grey or half-grey images, or videos that stop part way through. This often follows a card being removed, or the battery dying, while the camera was still writing.

Why memory cards fail

An SD or microSD card is a flash memory chip and a small controller sealed into one package. Most microSD cards, and many modern full-size SD cards, are monolithic: the memory and controller are a single piece of silicon with no separate chips or connectors inside. Typical causes of failure are:

• Removing the card, or losing power, while data is being written.
• Wear: every flash cell can only be written a limited number of times, and constant recording (dash cams, CCTV, drones) uses this up much faster than occasional photography.
• Physical damage: cracked cards, bent microSD cards, water, or broken contacts on adapters.
• Controller or firmware faults, which can make a card disappear without warning.
• Counterfeit cards that report more capacity than they really have, so files written beyond the real capacity are lost or corrupted.

What to do straight away

1. Stop using the card. Take it out of the camera, phone or drone and do not take any more pictures on it. New photos can overwrite the ones you want back.
2. Do not format it, in the camera or on a computer, and do not accept “repair” or “scan and fix” prompts.
3. Do not run CHKDSK or similar repair tools. They aim to make the file system tidy, not to save your files, and can discard damaged entries.
4. Lock it if you can. On a full-size SD card or adapter, slide the switch to the locked position before you put it in a computer reader.
5. Try one other reader. A different good-quality USB card reader is a sensible test. If the card still is not seen, or shows the wrong capacity, stop there.
6. Keep the card safe. Put it in a case, away from heat and magnets, and note what device it came from and roughly what is on it.

If the card reads normally in a reader and the problem is accidental deletion or a camera that complains about formatting, read-only recovery software can sometimes find the photos. Always save recovered files to your computer, never back to the card, and do not run several tools one after another on a card that is behaving erratically.

When a card needs a lab

A card that is not detected, shows the wrong size, is physically cracked or keeps disconnecting is unlikely to respond to software. Recovery then means working on the memory itself: on cards with separate chips this can involve reading the flash directly, while monolithic microSD cards need specialist work to access test points on the card. It is delicate, and the success depends on the condition of the memory, so it is worth getting the card assessed before anyone else attempts it.

We recover photos and video from SD, microSD, CompactFlash and other camera media, as well as USB sticks. See our SanDisk data recovery page and our service for external drives, flash media and camera cards in London.

Talk to us

If your memory card holds photos or footage you cannot replace, stop using it and call Data Retrieval on 020 7064 4996. We offer a free assessment with no obligation, or you can request a quote online.