I have need to add an external hard drive to my Dell 8930 XPS pc. I've tried but my Windows 10 Pro "sees" the drive and assigns it a drive letter but it does not show up in Drive Management and if I click on the drive Windows spins its wheels on something and never finishes. I have two other PC's with Windows 10 Pro but they are not UEFI Secure Boot and SATA set to RAID. Their setting is AHCI. The external drive works fine on them. What is the proper procedure for switching the Bios setting from RAID to AHCI on this new PC? That is the setting the new PC was shipped with. As far as I can tell Raid is not really being used. My pc has a PCIE NvME m-2 boot drive and a 2tb hdd. Any help someone can offer would be greatly appreciated.