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Not Accessible. Format the Disk?

The office of a mixed farm on the Charnwood side of the county runs on one ageing external drive: herd records, field maps, subsidy paperwork and fifteen years of accounts going back to before the current farm manager took over. It went from working to unreadable overnight. Every machine in the office reported it as not accessible and offered to format it, and one of the two people who use it very nearly said yes on the grounds that it had to be tried.

Hard DriveExternal DriveCorruption / Filesystem
// the job in four lines
MediaAn ageing external hard drive holding a farm office's records, accounts and mapping, which reports itself as not accessible and prompts to be formatted on every machine it is connected to.
What was reportedOld external hard drive, reports not accessible and offers to format, folders needed including herd records and accounts, the same message on more than one computer, a quote asked for by email.
Fault classLogical, on a tired surface. The structures that describe the volume had been damaged, so nothing could interpret the disk. Behind that, the drive had accumulated a number of weak sectors, which is very likely how the damage happened in the first place.
On the benchRead behind a hardware write blocker so no repair or format could be accepted, health and defect tables examined first given the drive's age, imaged on DeepSpar with weak regions deferred and revisited at reduced speed, the volume parsed from the image in R-Studio with the damaged structures rebuilt against their backup copies, remaining orphans matched by content signature, and everything validated and written to fresh media.
// reading the fault

Reading the fault

The prompt is not a diagnosis, it is a shrug. When a computer attaches a volume it reads a short description of the layout, then the index that describes the folders. If either of those cannot be interpreted, there is no error that means anything to a user, so the operating system falls back on the only remedy it has and offers to create a fresh, empty structure. It is the least useful moment to be offered the most destructive option.

Saying yes would not have wiped the disk, and would still have been a disaster. A quick format writes a new empty index over the old one. The files themselves stay where they are for a while, but the map that says which fragments belong to which document is replaced with a blank page, and rebuilding from that point means guessing at boundaries rather than reading them. On fifteen years of accounts the difference is enormous.

The reason it happened matters for what comes next. This was not a drive that had been mistreated. It was a drive old enough to have grown a spread of weak sectors, and a weak sector under the index is all it takes: one update that did not complete, and the structure describing everything else stops making sense. That means the volume can be rebuilt, and it also means the drive itself should not go back into service.

Most filesystems keep a spare copy of the important parts. There is a duplicate of the volume's description, and the index has mirrored records. A repair tool run on the live disk uses those too, but it writes its conclusions straight onto the drive as it goes, and where it is wrong there is no way back. Working from an image means the same reconstruction can be attempted, checked, discarded and tried differently as often as needed.

// bench work

Bench work

The write blocker went on first, which removed the possibility of anything accepting the format offer, including the bench. Because the drive is old, its health tables were read before anything else: the grown defect list was long, several hundred entries, and the pattern was spread rather than clustered, which is age rather than impact.

DeepSpar imaged it with the weak regions deferred, capturing the easy ninety-odd per cent while the drive was still cooperating, then returned to the difficult areas at reduced speed. R-Studio parsed the volume from the image, found the primary description unreadable and rebuilt it from the backup copy at the far end of the partition, then repaired the index against its mirrored records. A few hundred files whose entries had gone were matched by content signature. Everything was validated and written to fresh media.

// what went back

What went back

Herd records, mapping and the whole accounts history came back, with a small number of files recovered without their original names and returned in a separate folder so nothing was quietly misrepresented as complete. The old drive went back with a note recommending it be retired.

One disk is £300 + VAT. Nothing was opened and no parts were transplanted, so this ran under no fix, no fee, and the invoice followed the farm office confirming that the accounts opened.

When a drive asks to be formatted

Decline, unplug it, and do not connect it again to check whether it has recovered. The message means the description of the volume cannot be read, which is a problem in the bookkeeping rather than proof that the files have gone. Formatting replaces that bookkeeping with an empty one and makes everything afterwards harder. Avoid the check-and-repair tools as well, however respectable they look: they write their guesses onto the disk, and on an older drive the write itself can fail in a fresh place. If the drive is more than a few years old, assume the surface is part of the story and treat every further connection as spending something. Post it insured, or hand it in at the Cambridge reception on a weekday between nine and half past five.

Is this your drive as well? Every file on this page began with somebody describing a noise or a message, and the route in is the same each time. Nothing is charged for finding out what has happened. That examination finishes two working days after the parcel is logged in — never sooner, because rushing it is how evidence gets destroyed — and it ends in one number, written down, which does not move afterwards. Where a single drive is recoverable it is generally back with you two to four working days later. How you pay turns on which kind of fault it is, and the wording does not vary across this network: no fix, no fee all jobs except electronic and mechanical failures, chip level work, DVR and Forensic jobs. So a deletion, a broken file system, a lost partition, a firmware or service-area repair all keep the guarantee — nothing comes back, nothing is owed. Opening a drive under laminar flow, rebuilding a board, lifting a memory chip, or anything that arrived wet or burnt does not: half the agreed figure is taken before the work, and the balance only if your files come home. The published figures run: £250 + VAT for a memory card, a USB stick or a pen drive; £300 + VAT for any one hard drive or SSD, NVMe included; £400 + VAT for a recorder disk or a BitLocker volume; from £500 + VAT for an array, a NAS or a server; and £800 + VAT for a forensic investigation that ends in a written report. Five bands, all of them public, and the only one outside the guarantee is the forensic work. On packing: if the storage is screwed inside a laptop, a tower, a Mac or a server, take it out and send the bare unit, because dismantling equipment is not work this bench does. Three things go the other way and travel complete — an external drive in its own case, a NAS, and a WD My Passport or My Book with its cable, since on those the key sits on the bridge rather than the disk. A Fusion Mac needs both of its drives, labelled. A RAID or a server sends its member disks only, numbered by bay, with the front of the chassis photographed first. Flash soldered onto a mainboard, as on Apple Silicon Macs and many thin laptops, cannot be taken in at all, and neither can phones or tablets. Post it tracked and insured to Cambridge Data Recovery, Compass House, Vision Park, Chivers Way, Cambridge CB24 9AD, or put your own courier on it; the Cambridge reception takes devices across the counter too, Mon–Fri 9:00am–5:30pm. Nothing is collected, and there is no shopfront in the county to call at. Freephone 0800 689 0668. Packing notes and the shipping form live here.
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Each of these is a real enquiry, taken from a household or a business somewhere in Leicester or the surrounding county, with the name of the customer, the firm and anything else that would identify them taken out. What is left is the reasoning: what turned up, what had actually failed inside it, the method that fault required and the equipment it was worked on. One of the thirty-six is a job that was refused, and it belongs here every bit as much as the successes do.

// nearby on the shelf

Three more files along the same lines

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Is this your drive as well?

Examining it is free and takes 2 working days from arrival, the figure goes to you in writing and does not move afterwards, and a logical fault carries no fix, no fee. Start online or ring the freephone.