I recently got INTEL NUC Barebone (BOXNUC8I3BEH2) and installed Windows 10 Pro on Intel 2.5in 80GB SSD drive. All working perfectly. Then I tried to add ADATA SU800 128 GB M.2 SATA disk. The M.2 slot is enabled in (latest version of) BIOS.
When I insert the M.2 disk and boot, the orange HDD activity LED lights up and nothing else happens. I get nothing on screen so it is difficult to say what went wrong. I tried booting with and without the other drive. I also moved the ADATA SU800 to another PC (ASUS TUF H370) and it booted fine, I was able to see the disk and erase it from BIOS. So I assume that the disk is operational.
The ADATA SU800 is not on the Intel list of validated disks for this NUC, so I wonder if I should get one of the supported disks instead. I do not have any other M.2 drives at hand to try it out.
Could it be someting obvious I have misconfigured in BIOS?
EDIT: I can get to BIOS settings and also boot to Windows with both disks installed. The issue with seeing "nothing on the screen" may be related to the HDMI control. When I insert the M.2 and start the NUC, the screen does not wake up, so I have to switch the display off and on to get it working. The orange HDD activity light however switches on and stays on, so it does not work as activity light any more.
So my actual problem(s) with this M.2 disk seems to be that the HDMI does not wake up the screen and HDD led is on continuously. Using 2.5in SSD alone works fine, the HDD led blinks on disk activity and HDMI works as expected.