Data Recovery Case File · Solid State & Flash · The Index Survived Instead
Intact Structures With Unreadable Content Is the Reverse of the Usual Failure
His enquiry describes a device that appears to be working and is not. A stick where "the images are on it, it shows over 7 gigabytes used, but the images cannot be easily accessed" — and free software confirmed that all the files are present. That combination is unusual and specific: the filesystem is healthy, the listing is accurate, and the damage is in the file content itself, which is the opposite of how these devices normally fail.
| Media | 8GB USB flash drive reporting approximately 7GB occupied — filesystem listing complete and accurate; file content not opening; casing undamaged |
| Reported situation | Flash drive ceasing to read correctly · capacity used reported accurately · all files listed and confirmed present by consumer software · files not opening properly · device physically undamaged · recovery and possible repair of images requested |
| Fault class | Content regions degraded with filesystem structures retained — file data returning incorrectly while directory records remain accurate; image repair indicated for partially damaged files |
| Equipment used | Structural integrity distinguished from content integrity before any recovery route was chosen · imaged write-blocked at the block level with per-region read verification · unstable regions re-read across repeated passes and results compared · image files validated individually and structurally repaired where headers or streams were damaged · memory read past the controller where regions did not return |
The decode: why this is backwards, and what it means for the images
How flash devices usually fail: structures first. Directory records are rewritten constantly and wear out ahead of files that were written once, which normally produces missing folders and intact data.
Why his case is the reverse: the listing is perfect. An accurate space figure and a complete file list mean the filesystem structures are entirely readable.
What that leaves as the fault: the content regions. The device is returning something for each file, and what it returns is not what was written.
Why a device does that rather than reporting an error: flash storage corrects as it reads. Every read is checked and repaired using stored correction data, and a region degraded beyond that capacity returns corrected-but-wrong content rather than refusing.
Why that explains why the files list and do not open: the listing needs only a little correct data. A directory record is small and heavily protected, while an image is large and needs almost all of itself.
Why consumer software confirmed everything present without helping: it read the structures. Those tools report what the filesystem says exists, which is accurate here and says nothing about whether the content is sound.
Why repeated reading is worth doing rather than pointless: results vary. A marginal region returns differently on different attempts, and comparing many passes reconstructs the correct content for a good proportion of it.
Now the repair he asked about, which is a real and separate step: photographs tolerate partial damage. An image with a damaged header can be rebuilt from a known-good example of the same origin, and one damaged partway through often displays down to the damage.
Why that means the outcome is likely graded rather than binary: some will be perfect and some partial. The realistic expectation is a mixture, and it should be described that way rather than promised as complete.
What must not happen meanwhile: no repair tools and no copying files off repeatedly. Each read of a degraded region is a read it may not survive.
On the bench
Structural integrity was distinguished from content integrity before any recovery route was chosen — flash devices normally wearing directory structures first, so an accurate space figure and complete listing indicate the filesystem is entirely readable and the fault lies in content regions. Flash reads are corrected using stored correction data, and regions degraded beyond that capacity return wrong content rather than refusing. Unstable regions were re-read across repeated passes and results compared.
The outcome
Structural integrity distinguished from content integrity, regions re-read across repeated passes, and image files validated and structurally repaired individually. Free assessment, one fixed written figure including VAT; on flash devices where content has been deleted or overwritten, the figure is payable upfront. The decode: yours has failed backwards. Directory records are small and heavily protected, so they still list perfectly — while the images need almost all of themselves to be correct, and are not getting it.
Files that list correctly and will not open
Stop opening them and don't run repair tools — each read of a degraded region is a read it may not survive. Understand why it looks like nothing is wrong: flash storage corrects errors as it reads, so a region degraded past that capacity hands back content that's wrong rather than refusing, and consumer tools reporting all files present are reading the directory rather than checking the data. Expect a graded result: some images perfect, some partial, some rebuilt from their headers.
Stop opening them — call Cambridge Data Recovery on 01223 655015; structures distinguished from content, regions re-read across repeated passes, images validated and repaired individually.
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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.