Data Recovery Case File · Legacy & Obsolete Media · A Format Nobody Makes Now
Software Detecting Files and Failing to Return Them Is Reporting the Regions, Not the Files
His enquiry concerns a card format that has not been manufactured for many years. An old proprietary memory card taken from a camera where "the files do not appear when opening the drive, however it displays as having some storage taken up" — and recovery software "after detecting the files consistently fails to recover them." That pattern separates two things: what the card can describe, and what it can actually return.
| Media | Proprietary memory card of a discontinued format, taken from a camera — occupied capacity reported; file listing not presenting; consumer software detecting content without retrieving it |
| Reported situation | Proprietary memory card removed from a camera · card of a format no longer manufactured · files not listing when the volume is opened · occupied capacity reported by the host · recovery software detecting content · recovery consistently failing at the retrieval stage |
| Fault class | Content regions returning unreliably with structural information intact — detection succeeding on metadata while retrieval fails on the data itself |
| Equipment used | Detection distinguished from retrieval before any recovery route was chosen · card read on fixed contact equipment appropriate to its format rather than through a generic adapter · imaged with per-region read verification and unstable areas re-read across repeated passes · memory read past the controller where regions did not return · content carved by signature and validated by opening |
The decode: why detection and retrieval come apart, and what the format adds
What recovery software does when it detects a file: it reads a little. Detection requires only enough of a file's opening to recognise its type, which is a few hundred bytes.
What retrieval requires by comparison: everything. Recovering the file means reading its whole extent, which may be several megabytes.
Why that gap explains his result exactly: the openings read and the bodies do not. A card returning its first fragments reliably and failing further in produces detection without retrieval, every time.
Why the occupied capacity figure fits the same picture: it comes from structures. Space used is read from the filesystem's own accounting, which is small and near the start of the volume.
Why files nonetheless do not list: the directory sits elsewhere. The accounting can be readable while the records naming individual files are not.
What all of that points to: regional degradation rather than total failure. Parts of the card return and parts do not, which is a recoverable condition.
Why repeated reading is the method rather than better software: results vary. A marginal region returns differently on different attempts, and comparing many passes reconstructs correct content for a good proportion of it.
Why consumer software cannot do that: it asks once. A tool that requests a region and receives an error moves on, because it is not designed to spend minutes on a single fragment.
Now the format, which changes the equipment rather than the prospects: it is proprietary and discontinued. Cards of that family use their own interface and are read on equipment that supports it, rather than through a general adapter.
Why the age is not itself a problem: stored content is stable. Flash memory holds its charge over long periods, and a card that has sat unused has not degraded because of the years.
On the bench
Detection was distinguished from retrieval before any recovery route was chosen — detection requiring only a few hundred bytes of a file's opening to recognise its type, while retrieval requires the whole extent, so a card returning first fragments reliably and failing further in produces exactly detection without recovery. Occupied-capacity figures come from small filesystem accounting structures, which can read while directory records do not. Unstable regions were re-read across repeated passes.
The outcome
Detection distinguished from retrieval, the card read on equipment appropriate to its format, and regions re-read across repeated passes. Free assessment, one fixed written figure including VAT; on cards where content has been deleted or overwritten, the figure is payable upfront. The decode: detecting a file needs a few hundred bytes and recovering it needs all of it. Your card is returning openings reliably and bodies unreliably, which is why every tool finds them and none retrieves them.
When software finds your files but cannot recover them
Stop rerunning it — the result won't change, because detection and retrieval are different demands. Recognising a file's type takes a few hundred bytes of its opening; recovering it takes the whole extent, so a card returning openings reliably and bodies unreliably produces exactly that pattern. Consumer tools ask once and move on rather than spending minutes on a single fragment. Take some encouragement: it means parts of the card read fine, which is regional rather than total failure.
Stop rerunning it — call Cambridge Data Recovery on 01223 655015; detection distinguished from retrieval, read on equipment matched to the card format, regions re-read across repeated passes.
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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.