It is the characteristic SATA SSD failure and it confuses people, because every health indicator said the drive was fine. Wear reporting and the thing that actually failed are two different subsystems.
An 860 EVO spreads your data across V-NAND dies and keeps a translation layer recording where every block physically sits. Lose that layer and the drive still holds everything, with no way to present it.
The 860 EVO is one of the most widely sold SATA SSDs ever made, which means we see a great many of them, and they fail with a consistency worth documenting. The drive works normally with no degradation, no SMART warning and no slowdown, and then simply is not there.
What has happened is the MJX controller has stopped responding. Not the flash — the NAND behind it is generally in good condition with plenty of endurance remaining. The chip managing it has locked up or failed, and with it goes the drive's ability to present itself to the machine at all.
That distinction matters because it means the data is almost always still physically present. The problem is access, not loss.
Stop power-cycling it. The instinct is to keep trying different ports and machines. A controller that enumerates intermittently is a considerably better prospect than one that has stopped entirely, and repeated attempts can end that.
Do not run a firmware update. Samsung Magician will offer one. Flashing firmware to a drive with a failing controller can complete partially and leave it in a worse state than before.
Do not initialise it. If it appears in Disk Management as uninitialised, that prompt destroys the partition structure. Decline it.
Check whether encryption was on. BitLocker hardware offload and Samsung's own encryption both apply here. Without the key, reading the NAND achieves nothing.
The first is vendor mode — a Samsung engineering interface that allows the controller's firmware and translation tables to be examined and repaired. Where the controller responds at all, this is the preferable route because the drive reassembles its own data.
Where it does not respond, the NAND is read directly. The memory is accessed and the raw flash extracted, then reassembled by reversing what the controller was doing — wear levelling, interleaving, scrambling and error correction, all specific to the MJX controller and its firmware revision.
That reassembly is the difficult part. Raw NAND without correctly reversing the controller's arrangement is noise, which is why this is not a matter of plugging chips into a reader.
The pattern is consistent enough that we recognise it on sight: sudden total absence with no prior symptom, on a drive whose flash is in good health. Samsung has not characterised it as a defect.
Possibly, if it is in date. A warranty replacement gives you a new drive and not your data — the failed one is not returned. Recover first if the data matters.
No, and attempting one on a failing controller can make things worse. Updates are for healthy drives.
Rarely. These arrive with substantial endurance remaining. The controller has failed, not the memory.
From £300 +VAT, fixed in writing after the free diagnostic.