The structure describing how your drive is divided occupies a few hundred bytes at the very front of it. Damage those and the operating system reports an empty disk — not because anything moved, but because the map has gone. The territory is all still there.
$ cdr diagnose /dev/sdb → Device: Seagate HDD (2 TB) → Status: PARTITION LOST — drive reads as RAW → Client: confidential · Cambridge CB2 $ cdr engineer-working → Read-only image: taken · source untouched → Partition table: rebuilt + remounted → File system: structure intact · files visible $ cdr verify → ✓ documents — 14,210 files → ✓ photos — 21,540 files → ✓ partition recovered — files back
Losing it makes a full disk look empty, and that is exactly what has usually happened.
At the very start of a disk sits a small structure listing where each partition begins and ends. On older disks that is the MBR, occupying 512 bytes; on modern ones it is GPT, with a backup copy at the far end of the disk. Either way it is a tiny map, and everything the operating system knows about the layout of your storage comes from it.
Damage those few kilobytes and a completely intact drive reports as unallocated or unformatted. Every file is still there, in exactly the same physical location as before, and nothing can find them because the map has gone.
This is why a drive showing as raw or empty is so often a straightforward recovery. Nothing has been lost except the index, and the index can be rebuilt from the volumes it was describing.
Reconstruction does not mean writing a plausible partition table and hoping. Every file system leaves recognisable structures at the start of its volume — NTFS boot sectors and MFT records, ext4 superblocks, APFS containers, exFAT boot regions. Scanning the whole disk for those signatures reveals where each partition actually began.
Those findings are then cross-checked. A boot sector claiming a volume of a particular size should be followed by a file system of that size, and a backup superblock further in should agree. Where all of it agrees, the original layout has been found rather than approximated.
GPT disks are easier still, because GPT keeps a full backup copy of the table at the end of the disk. A surprising number of these resolve from that backup alone.
Do not let Windows initialise the disk. When a disk shows as unallocated, Disk Management offers to initialise it. Accepting writes a fresh, empty partition table over the damaged one and destroys the evidence needed to work out the original layout.
Partition recovery is logical-class work from £300 +VAT, fixed in writing after the free diagnostic. Where the underlying disk is also physically failing, that is mechanical class and quoted accordingly — you are told which at the diagnostic.
No fix, no fee applies to logical work throughout.
Classic partition table loss. The data is almost certainly entirely intact and unreferenced. Do not initialise the disk when Windows offers — that writes over the structure needed to work out the original layout.
No. Initialising writes a new empty partition table. It is the single most damaging thing available at this point and it is presented as the helpful default.
Common. Interrupted resize operations leave the table describing boundaries that no longer match the file systems. Recoverable, and the original layout is usually derivable from the volumes themselves.
It is a capable tool and it does write to the disk. If the data matters and you are not confident, that write is the risk. If you are going to try, work from a read-only image rather than the original.
Different problem, and do not treat it as a partition fault. That usually means the array is not assembling. Take the whole set out of service and send every member.
Two to five working days. Scanning a large disk for file system signatures is the slow part, and it scales with capacity rather than with how badly damaged the table is.
A free diagnostic, no fix no fee on most jobs, and lost-partition recovery off any drive, stick or card — every file back intact. Begin your recovery today.