Samsung 850EVO driver failure

I have 4 x 850 EVO (250GB) and two have "failed". The first symptom appeared when the drives disappeared from explorer and disk manager wouldn't initialize them or format them ("error occurred").

I booted into GPARTD wiped the disks and formatted to FAT32 (also tried new UUID) and everything came up ok in Windows. Format works with no problems, so I tried to write / delete data from them (simple batch file copy / del) and explorer hangs.

I've used Samsung magician to update the firmware then tried a bench test and again this hung explorer.

Everything works fine with the drives out.

RMA? or I have missed something?

Have you tried a secure erase on the SSDs?

you can create a bootable usb stick for it in the magician software

It starts the erase but just hangs, I'll try it bootable

That didn't work either

Replace the cable/test the drive in one of the SATA ports that on a working drive to determine if its a cable/port/mobo problem.