You need to format the disk · the disk was not readable · RAW · corrupted and unreadable
Windows says you need to format the disk in drive E: before you can use it, or reports the file or directory is corrupted and unreadable; Disk Management shows the drive as RAW; the Mac says the disk you inserted was not readable by this computer and offers to initialise it. Every one of those means the same thing: the drive answered, but the file system on it could not be read. Sometimes that is damage to the file system on a healthy drive, from a disconnect or a crash, and it is rebuilt on an image. Often it is a drive with weak heads or bad sectors that has failed to read the part of itself that holds the file system, and it is a drive that needs imaging before anything else. In either case the answer to the prompt is no. One drive is £300 + VAT after the free look, fixed in writing, 3–4 days at the bench.
Rather talk it through? An engineer answers the bench line
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A file system is a small index at the front of the drive and a set of tables scattered across it: the partition table, the boot sector, the master file table on NTFS or the catalogue on HFS+ or the object map on APFS. The files themselves are elsewhere, and they are the last thing to be touched. When the index cannot be read, the computer has nothing to show you and, in the only way it knows, offers to write a fresh one. That is the format prompt. It is the computer's shrug, not its verdict.
Two things make an index unreadable. The first is damage to the index itself on a drive that is perfectly well: a disconnect while writing, a crash, a power cut, a bridge that quietly translated sectors differently from the last one. Those are rebuilt on an image, and the odds are good. The second is a drive that cannot read the sectors the index lives on because its heads are weak or the surface has bad sectors there. The prompt looks identical; the drive is not, and it must be imaged head by head before anyone goes looking for the index.
That is why the bench never tries to repair a file system on the original drive, and why chkdsk and First Aid are dangerous here. Both write. On a damaged index they can make a bad situation permanent by rebuilding it wrongly; on a weak drive they hammer the weakest part of it. The drive is imaged first, once, and the file system is put back together on the image where nothing can be lost by trying.
| What you see | The usual reason | Where that leaves you |
|---|---|---|
| You need to format the disk in drive X before you can use it | Windows cannot read the file system | Cancel; the files are there |
| The disk you inserted was not readable by this computer | The Mac cannot read the file system | Ignore; do not initialise |
| Disk Management shows RAW | The partition is present but its file system is not recognised | Imaged; file system rebuilt on the image |
| The file or directory is corrupted and unreadable | Damage in the NTFS tables | The same |
| Location is not available / access is denied | The volume is mounted but its structures are damaged | The same |
| Disk Utility: First Aid found the volume corrupt and could not repair it | Damage beyond what First Aid handles | Do not run it again; send it |
| The same drive was fine yesterday | A disconnect or crash, or a drive beginning to fail | The free look tells which |
A case number goes on it the day the parcel is opened, and an engineer settles what has actually failed before anything else happens. A drive that clicks or beeps is not powered again; one that spins is read on our own imaging equipment, never in a computer that will retry and time out and retry. Back to you come two things together: a straight note of what is liftable and what is not, plus one figure, fixed and written down. Accept it, or decline and owe us nothing.
Every external drive is two things: the drive, and the USB board that talks to it. The board is checked first, because a failed bridge, a snapped socket or a dead regulator is the whole fault on a good share of jobs, and because on WD's encrypted drives the board holds the key. Where the drive itself has stopped, it comes out of its case onto the bench.
Stuck or failed heads are replaced with a matched set from a donor, seized spindles freed, and firmware faults corrected in the drive's service area from the terminal. The drive is not repaired to be used again; it is made to read once, in a single careful pass, and that pass is planned before it begins.
Nothing is worked on live. The whole drive is imaged once, head by head and weak areas last, with reads timed to what the platters can stand, and the file system is put back together on the image. Encrypted volumes are unlocked there too, with the original board's key or the password you supply, and never on the original.
What was recovered is listed for you first, and only then does a bill exist. Approve the list and it is invoiced; turn it down and it is not — and where nothing has come back, most jobs carry no charge at all. Recovered data travels home on fresh media bought in for your job, with the postage at our end. Your case is not closed until you have opened the files on a machine of your own.
The owner clicked Cancel, unplugged it, and sent it, which made this a two-day job instead of a lost cause. On the bench the drive was healthy; the power cut had left the NTFS master file table half-written. The drive was imaged, the file table repaired on the image from its mirror, and every folder came back with its name.
Illustrative example — replace with a genuine caseNo. It means Windows cannot read the file system, not that the drive is empty. Click Cancel, unplug it, and send the form.
No. Initialise writes a new, empty partition map over the one that holds your files. Click Ignore, unplug it, and send the form.
If the drive is perfectly healthy and only the file system is damaged, sometimes. If the drive is also slow, ticking or dropping out, it will make things worse. The bench images first, then rebuilds on the image, which software running on the original cannot do.
£300 + VAT for one drive after the free look, fixed in writing.
Often two or three days for a healthy drive with a damaged file system; 3–4 days at the bench where the drive itself is failing.
The file system is rebuilt on an image, where nothing can be lost by trying. The first look is free, and the figure is in writing before any chargeable work.