If you clean install with the system set to AHCI it will work. However it wont see the HDD unless it too was formatted with AHCI If you put it on a drive wire or in a dock you can recover and then use diskpart to clean the drive so that you can remove the M2 and install clean ahci for the HDD. If you dont want to use hdd as boot but rather as data then use DISKMGMT.MSC. to format the HDD as AHCI and EXFAT FORMAT. Drive wire [URL] DOCK [URL] [IMAGE]Drive Dock [IMAGE]SN550 is AHCI PCI-E mkey only[IMAGE]M2 Drive types
Just got my new R10 with the 6800xt and ryzen 5 5600. I only ordered it with an old fashioned hdd for some reason but I did get aio, 16g dual channel, & 1k psu. I bought a WD black 1 tb nvme ssd and want to make it the boot drive with windows and some games/programs. I searched and am still confused as it seems people had trouble using migration software and not being able to boot or issues. What is the best way to install and put windows and my Alienware/dell software on the nvme ssd as the boot drive and make the hdd just for data and storage. Thanks 
Aurora R10, help upgrade HDD to NVMe SSD