Data Recovery Case File · Cameras, Drones & Cards · Visible on the Camera, Invisible to the Computer

Recover Photos From an SD Card: Visible on the Camera, Not on the Computer

The enquiry contained one observation that is worth more than any diagnostic tool, and a reason that made it matter. A SanDisk SDHC 4GB card from an old camera: "the photos can (just about) be viewed using the camera, so I know they are there, but they seem to be corrupted and won't download to a computer. Tried at home and at a photo shop." Then, quietly: "my mum died last year and a lot are of her, so I could do with them recovering if possible." The technical decode below is genuinely encouraging, and it starts from that first observation — because "I can see them on the camera" is hard evidence that the image data exists, and it explains precisely why a computer refuses what a camera manages. The two devices are not disagreeing about whether the photographs are there. They are asking the card two completely different questions.

The decode: why the camera can and the computer can't

Two devices, two questions: a camera's firmware is small, purpose-built and forgiving. It knows the card's layout, it looks for image files in the folder it expects them in, and it will happily display a picture whose surrounding structures are damaged — because all it needs is enough to find the file and start decoding it. A computer is doing something much stricter: its operating system must mount the card as a volume, which means validating the partition structures, parsing the filesystem, and building a consistent picture of every file and folder before it will show anything at all. If that validation fails, the computer refuses the whole card rather than showing some of it. So the camera's "just about" and the computer's flat refusal are entirely consistent — one is reading pictures, the other is reading bookkeeping.

Why "I can see them on the camera" is such good evidence: it establishes the thing that actually matters. The images are physically present on the card and readable enough to decode and display. That rules out the two worst scenarios — a card that has been erased, and a card whose memory has failed — and leaves the recoverable one: intact photographs behind damaged organisational structures. In practical terms, being able to see them on the camera means the recovery is very likely to succeed.

The one thing to be careful of: a technical caution that matters for the result. Every camera image carries an embedded thumbnail — a small preview version stored inside the file so the camera can display it quickly. When structures are damaged, some recovery approaches return those previews rather than the full-resolution originals, and the difference is not obvious until you try to print one or look at it on a large screen. For photographs of someone's mother, that distinction is the whole job. Proper recovery separates the two deliberately and validates the output at full size.

And the trip to the shop: worth noting kindly. A photographic retailer's equipment is built to read healthy cards quickly and reliably — it is not diagnostic equipment, and a card that will not mount is outside what it can do. Their inability to help is not a verdict on the card; it simply means the question had moved past what a transfer kiosk can answer.

On the bench

The card was imaged write-blocked behind the DeepSpar USB Stabilizer 10Gb — one careful pass, with timeouts enforced so no struggling region could stall it — and everything after that happened on the copy, where nothing could be lost by a wrong turn. The damaged filesystem structures were reconstructed until the volume stood up with its folders and original filenames; where reconstruction could not reach, signature carving recovered images directly from the card's contents, with full-resolution originals deliberately distinguished from the embedded previews so that nothing came back as a thumbnail pretending to be a photograph. Every image was then validated by being displayed at full size and looked at. The set was ordered by capture date and delivered on fresh media, with the original card returned untouched.

The outcome

The full-resolution photographs recovered from the imaged card, validated individually and delivered. Free assessment, one fixed written figure including VAT, no recovery, no fee. The decode, for anyone who can see their pictures on the camera but cannot get them off: a camera reads image files with forgiving, purpose-built firmware, while a computer must validate and mount the whole volume before showing anything — so the disagreement is about bookkeeping, not about your photographs; being able to view them in-camera is strong evidence the image data is intact and the recovery is likely to succeed; and insist that what comes back is full-resolution originals rather than the embedded previews, because the difference only becomes visible when the picture matters most.

Our case files are drawn from genuine enquiries received by our laboratory over the past ten years, anonymised to protect client confidentiality. Each one describes the diagnostic and recovery procedure our engineers apply to that fault, using the equipment listed.