Data Recovery Case File · Formatted & Logical Faults · Do the Proportion
A Gigabyte on a Two-Terabyte Drive Occupies One Twentieth of One Percent of It
His enquiry reports the damage with a precision that makes the outcome largely calculable. A 2TB drive "formatted by accident and overwritten with 1GB of data, so I lost the partition record and the former file structure", on a drive that was around 65% full — and he would like the content back "in its original shape." The two figures he supplies settle most of the question: the overwrite is negligible, and what was lost is the description.
| Media | 2TB hard drive formatted in error and subsequently written to with approximately 1GB — prior content approximately 65% of capacity; partition record and directory structures lost |
| Reported situation | 2TB drive formatted accidentally · approximately 1GB of new content written afterwards · partition record lost · previous directory structure lost · drive previously approximately 65% occupied · recovery sought with original names and folder arrangement · photographs and documents identified as the priority |
| Fault class | Format with minimal subsequent writing — content regions substantially retained; recoverability of naming determined by survival of duplicate directory records |
| Equipment used | Overwritten proportion calculated from the owner's figures before any recovery route was chosen · drive imaged write-blocked at full physical capacity before any interpretation · partition boundaries reconstructed from filesystem signatures rather than from the table · directory records recovered from duplicate copies across the volume · content carved by signature and matched against recovered records |
The decode: the arithmetic, and what original shape depends on
What the proportion actually is: a gigabyte against two thousand. The new content occupies roughly one twentieth of one percent of the drive, which is as close to nothing as makes no difference.
Why that is the decisive number: overwriting is the only irreversible part. Everything else the format did affected descriptions rather than content.
What a format writes and what it does not: structures, not zeroes. It creates a fresh empty filesystem and marks the capacity available, leaving the previous content physically in place.
Why he correctly identifies the losses: the partition record and the directory. Those are what a format replaces, and without them nothing knows where the volume began or what any file was called.
Why the partition boundary is recoverable without the record: the filesystem announces itself. A volume leaves recognisable structures at its start, and those identify where it began independently of any table.
Now original shape, which is his real request: that means names and folders. Content can be recovered by recognising file structure, and names cannot be recovered that way at all.
Where names actually survive: in duplicate records. Filesystems keep backup copies of their directory structures elsewhere on the volume, and those frequently outlast the primary ones a format replaced.
Why the 65% figure helps here: it locates them. A drive two-thirds full has its structures spread across a known proportion, and the regions the new filesystem occupied are a small part of that.
What the realistic expectation is: most content, much of it named. Where duplicate records survive the tree returns intact; where they do not, that portion comes back by type and date instead.
What must happen now, and it is the only variable left: nothing further written. The gigabyte is negligible and a hundred more would not be.
On the bench
The overwritten proportion was calculated from the owner's figures before any recovery route was chosen — one gigabyte against two thousand occupying roughly one twentieth of one percent, while a format writes structures rather than zeroes and marks capacity available with prior content physically in place. Partition boundaries were reconstructed from filesystem signatures rather than from the table, and naming depends on duplicate directory records surviving elsewhere on the volume.
The outcome
Overwritten proportion calculated first, the drive imaged at full physical capacity, and records recovered from duplicate copies. 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: your two figures answer most of it. A gigabyte on two terabytes is one twentieth of one percent — so what you lost is the description, and descriptions keep spare copies.
After an accidental format
Write nothing further to the drive and work out the proportion — it's usually far more encouraging than it feels. A format writes structures rather than zeroes, so what's genuinely gone is only what later use physically replaced, and a gigabyte on a two-terabyte drive is one twentieth of one percent. If you want the original names and folders back, that depends on duplicate directory records surviving elsewhere on the volume, which they frequently do. The one remaining variable is what you write next.
Write nothing more — call Cambridge Data Recovery on 01223 655015; overwritten proportion calculated first, boundaries reconstructed from filesystem signatures, records recovered from duplicate copies.
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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.