Cause of loss · a RAW volume
Hand Windows a volume it cannot interpret and Format is what you are offered, because Format is all it has in stock. The hardware sits there unharmed; what is written across it has simply stopped adding up. Far more data goes to people in Plymouth accepting that offer than to the corruption which raised the box.
You will be talking to an engineer
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| What happens | What that points to | What to do |
|---|---|---|
| The drive is not accessible. Windows offers to format it before it will open. | Windows can make nothing of the file system, so it reports RAW | Ignore that prompt |
| CHKDSK is not available for RAW drives. | CHKDSK never starts — there is no file system for it | Disconnect it from the PC |
| File or directory corrupted and unreadable (0x80070570) | Entries in the MFT that no longer read | Close the window and stop browsing |
| Disk structure is corrupted and unreadable (0x80070571) | Damage to the partition table or the MFT | Image it first, repair it later |
| The parameter is incorrect — X:\ not accessible. | Broken structures over failing sectors | Treat it as a hardware fault too |
| …does not contain a recognized file system | Nothing left that names a file system | The contents have not gone |
| The disk you inserted was not readable (macOS) | macOS wording for the same fault. Initialize is the button to avoid | Eject it, and never Initialize |
Whatever arrives is booked in under a case number on the day it reaches the bench. An engineer then works out the actual fault, and that part is free. You get a plain answer on what can come off the drive and what cannot, followed by one price in writing. Nothing further happens until you have read it and agreed.
Nothing gets repaired before a sector-by-sector copy exists, with every poorly-reading area logged and left for the end. Broken structures and tired hardware usually arrive together, and one image deals with both.
All of it happens inside the image and never on your drive: partition table, boot sector and MFT are reassembled there, so a step that goes badly can be rolled back and repeated.
However bad the MFT is, the contents of the files remain in the clusters they always sat in. Each file gets carved out of the image on its signature alone, and whatever folder structure the surviving records will support is put back around them.
Thinking it over costs you nothing. Everything the drive gave up is listed for you before any invoice exists, and the bill only follows your go-ahead. Files travel back on media bought in for your job, with return carriage paid at this end, and the case stays on the bench until you confirm they open on your own computer.
Every one of these tools shares a habit: CHKDSK, Disk Utility's First Aid, whichever free RAW repairer a forum is pushing this month — each writes to the very disk it claims to be mending. If the hardware beneath is healthy, no harm follows. If it is not, what might have returned whole returns in pieces. Caution costs you a single day, waiting on an image.
The lead came out while the disk was being written to. By morning Windows had one suggestion, and it was to format. The 4TB was imaged in full before anything else, and every repair after that was made to the copy — the boot sector first, then the ruined mirror of the MFT. Nothing at all went back to the original. Fifteen years of client work returned, folder tree intact.
Turn it down. Format writes a clean, empty file system straight over the damaged one, landing exactly on the records that hold your folder names, their structure and their dates — and it is from those records that a rebuild is assembled.
It means Windows can no longer interpret the structures describing the volume — most often the boot sector, the Master File Table or the partition table. Your files lie underneath all that and are not affected.
Nothing is gained by it. Against a RAW volume CHKDSK will not even start, and where the hardware is worn, every repair pass costs a little more of it. That work belongs on a copy, never on the original disk itself.
Very likely, and you have plenty of company. Yank the cable mid-write and the index is left unfinished, still pointing at files that are perfectly sound.
The diagnosis is free, and it comes back as a list: which files read, which do not, and what getting them off would take. Until then, leave the drive unplugged.