Hi, I've just bought a 256GB SanDisk X400, M.2 SSD, SATA III for my XPS 13 9343. I have just installed it and switched on the machine. The bios is saying "MiniCard SSD Device = (none). Obviously the Windows 10 install can't see anything either. Is this drive incompatible with this laptop? Should I be replacing it with a Samsung 250GB 850 EVO M.2 SATA SSD instead?
You need the SATA version for this model - yes. The newest XPS 13 supports PCIe/NVMe drives, but the older one you have does not.
Sorry, I don't understand, the SanDisk I bought IS SATA.