Data Recovery Case File · Formatted & Logical Faults · The Wrong Partition
A Drive Showing a Small Partition Is Showing One of Several, Not All of Itself
His enquiry contains a discrepancy that explains itself once separated. A machine that will not start and asks for a recovery disc he does not have, with the drive mounted in a cradle where "the drive appears full and only 100MB in a partition" — though it is a 500GB drive with under 200GB used. What he is seeing is one partition and not the drive, and the small one is not where his files are.
| Media | 500GB system hard drive from a machine that will not start — connected externally, presenting a small partition reported as full; main volume not presented |
| Reported situation | Machine of an earlier operating system generation not starting · start-up requesting recovery media not available to the owner · drive removed and connected through a cradle · a partition of approximately 100MB presented and reported as full · main volume not visible · approximately 200GB of music and photographs held · content required |
| Fault class | Partition table partially readable — small system partition presenting while the main volume entry is unreadable; content unaffected |
| Equipment used | Presented partition identified as a system reserved volume rather than the data volume · imaged write-blocked at the block level before any interpretation · main volume boundaries derived from filesystem structures within the image · filesystem interpreted with its duplicate copies · content reconciled against expected occupancy |
The decode: what the small partition is, and where the rest went
Why a system drive has more than one partition: installations of that generation create a small reserved volume alongside the main one. It holds start-up components and recovery tools, and it is typically a few hundred megabytes — deliberately small and deliberately separate.
Why that matches what he is seeing: a partition of around 100MB reported as full is exactly that reserved volume. It is full because it was sized to fit its contents with little to spare, which is normal rather than a symptom.
What the absence of the main volume means: its entry in the partition table could not be read or does not parse. The table describes several volumes, and one being unreadable does not prevent the others presenting — so a partial read shows a partial drive.
Why the drive appearing full follows from that: the system is reporting the only volume it can see. Occupancy is being read from the small partition rather than from the drive, and it is describing 100MB rather than 500GB.
Why none of this implicates his content: the main volume occupies the overwhelming majority of the drive and has not been touched. What is damaged is a few bytes describing where it begins, in a table at the very start.
Why the machine asking for recovery media fits the same fault: a system that cannot find its main volume asks for the media that would repair it. The request is the consequence rather than an additional problem.
Why he must not obtain and use that media: a recovery process offers to repair the start-up configuration, and a repair writes to the partition table. The very structure that needs reconstructing is the one it would rewrite.
How the main volume is recovered without it: a filesystem has a recognisable beginning and records its own extent. Finding where it starts and how far it runs reconstructs the partition from the inside, without the table entry that was lost.
Why the occupancy figure he remembers is useful: under 200GB used on a 500GB drive. A reconstruction producing roughly that much content is verified, and one producing something very different has gone wrong.
What must not happen: no formatting the small partition, no creating a new volume in the unallocated space, and no accepting any offer to repair. The rest of the drive appears as free space, which invites exactly those actions.
On the bench
The presented partition was identified as a system reserved volume rather than the data volume — installations of that generation creating a small reserved partition of a few hundred megabytes holding start-up and recovery components, sized to fit with little spare so reporting as full is normal. Absence of the main volume indicates its partition table entry being unreadable while others present, so occupancy is reported from the visible partition. Main volume boundaries were derived from filesystem structures within the image.
The outcome
The visible partition identified as a system reserved volume, the drive imaged at the block level, and the main volume reconstructed from filesystem structures 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: you are seeing one partition rather than the drive. That small full one is the reserved start-up volume — and your main volume is undescribed rather than absent.
A drive showing a small partition and reporting itself full
Don't obtain recovery media and run it, and refuse any offer to create a volume in what looks like free space — a recovery process repairs the start-up configuration by writing to the partition table, which is the structure that needs reconstructing. What you're seeing is one partition rather than the whole drive: installations create a small reserved volume of a few hundred megabytes for start-up components, sized with little spare, so full is normal for it. Your main volume's table entry is unreadable while the reserved one still presents — which leaves your content undescribed rather than absent.
Don't run recovery media — call Manchester Data Recovery on 0161 871 0788; visible partition identified as a reserved volume, imaged at the block level, main volume derived from filesystem structures within.
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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.