Data Recovery Case File · Formatted & Logical Faults · A Description That Does Work

Unallocated Means the Map Was Lost, and He Can Describe Exactly What It Mapped

His enquiry is the most precisely written kind. A drive in a plain external enclosure holding around 950GB of pictures and video across a known folder structure on a single known filesystem, where the "partition has been lost and is now unallocated, following a hang and subsequent reboot." The loss is a structural one — and the specificity of his description turns a general search into a targeted one.

The decode: what was lost, and how his detail is actually used

What "unallocated" reports: the system read the small structure at the drive's start describing how the space is divided and found nothing it could interpret. With no readable division, it describes the whole drive as unassigned — which is a failure to read rather than a discovery that the drive is empty.

Why a hang and restart produces this: the structure describing the partition is written like anything else. An interruption while it is being updated, or a write that never completed before the machine stopped responding, can leave it inconsistent — and a partition record that does not parse is a partition that does not appear.

Why the content is very likely untouched: the structure occupies a tiny area at the very start of the drive. The 950GB sits where it was written, entirely unaffected by damage to the description of where it begins and ends.

How the boundaries are recovered without that structure: a filesystem has its own recognisable beginning, and its records describe its own size. Finding where the filesystem starts and how large it says it is reconstructs the partition from the inside out, without needing the original record at all.

Why knowing the filesystem type matters: it tells us what to look for and where its duplicate records are kept. Filesystems maintain secondary copies of their key structures elsewhere on the volume, and knowing which one is in use means going straight to the right locations rather than testing possibilities.

Why the folder structure he described is genuinely useful: it gives an expected result to check against. A reconstruction that produces two main folders containing the subfolders he named is verified, and one that produces something else has gone wrong — which is a test that would otherwise not exist.

Why listing the file formats helps too: where structures cannot be rebuilt, content is found by signature. Knowing the specific image and video formats present means carving is targeted at those patterns rather than searching for everything, which is faster and produces fewer false results.

Why the enclosure being a plain one is worth confirming: some external units alter how data is written, so a drive read directly presents unreadably. A plain enclosure without array configuration passes the drive through unchanged, which removes that possibility.

What must not happen: no accepting an offer to initialise or create a new partition. The system regards the drive as unassigned space and will offer to make it usable — and that writes a new structure over the region reconstruction reads.

On the bench

Supplied structural detail was used to target reconstruction rather than search blind — a partition reported as unallocated indicating that the structure describing the drive's division could not be interpreted, commonly following an interrupted update, while content remains in place. Partition boundaries were derived from filesystem structures within the image, a filesystem carrying a recognisable beginning and recording its own extent, so boundaries are reconstructed from the inside without the original record. Duplicate filesystem records were compared against the primary set.

The outcome

The supplied detail used to target reconstruction, the drive imaged at the block level, and boundaries derived from the filesystem within. Free assessment, one fixed written figure including VAT; where a drive has to be opened, 50% of parts and labour is payable upfront with the balance only on success — otherwise no recovery, no fee. The decode: unallocated means the map could not be read, not that the drive is empty. Your filesystem records its own extent, so the partition is rebuilt from the inside — and the folder structure you described gives us a way to check the result.

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.