I stayed up way too late last night banging my head against the wall trying to figure this out and following every bit of advice that I could from increasingly less-related google searches... I just (mostly) completed a build for my parents, and it includes an Asus Prime z370-a motherboard and a Samsung 960 EVO (500G). I've also got a 4TB platter drive and an optical drive, but I've left those disconnected for now. I have flashed to the newest version of the z370 BIOS (March 2018). When I boot into the BIOS, the 960 EVO is present about 10% of the time. I've switched between the M2_1 and M2_2 slots on the motherboard, and seen no difference. I've changed the settings for the M2 slots to UEFI only, ensured that they are running at x4, disabled CSM, changed secure boot options, etc. I have also been reverting my BIOS settings back to default before attempting additional changes, so that the only changes that persist are ones I can remember. When the drive has shown up in BIOS, I've proceeded along to try to install Windows 10. If the drive had shown up in BIOS, it is about 25% likely to show up as an available drive for the Windows install. I've followed a bunch of troubleshooting steps that I've found when googling for drives not appearing in the Windows installer, but many of them require more BIOS changes, and I'm back to not being able to reliably get the drive to appear at all in BIOS on the subsequent reboots. I've had the 960 EVO appear in BIOS, appear as an available drive for Windows installation, and then had it error out as no drive found when the drive list refreshed. I also managed to get through the process to actually have my Windows installation begin, and then error out with a "corrupted installation file" error (recommending me to re-create my installation media) when it had almost completed. I created a UEFI thumb drive using the Windows utility, and I have also downloaded an ISO and created a thumb drive using Rufus. The Rufus-created thumb drive is the one that failed near the end of the installation with the "corrupted installation file" error. The very next time that I was able to see my 960 EVO in BIOS and proceed into the windows installation, it showed 4 partitions, all from my 960 EVO (presumably the partitions that it created during the recent failed installation). When I attempted to remove those partitions, I received an error that no partitions were found, and then when the list refreshed, it was completely blank again, with no drives found. I checked DiskPart and it also found no available partitions (apart from the USB that held my Windows installer). After 3-4 more reboots, with the 960 EVO not showing up in BIOS again, I finally threw in the towel because it was 4am, and I had to get up for work in 2 hours. Any advice? Is the drive faulty? What else can I try?