Windows 10: Changing from AHCI to RAID causes boot loop

I have a MySN XMG U716 (Clevo P775DM1) that I got with two 256Gb Samung 951 NVMe PCIe SSD's, initially in RAID 1. I later decided to break this RAID array because I wanted the extra 256Gb for games etc, and I broke the array by setting them to Non-Raid but leaving RAID mode enabled.

Somehow the BIOS has been set back to AHCI (possibly by the BIOS and KBC/EC Firmware Updates I've done, although I'm not fully convinced that it wasn't something else), but Windows boots just fine in AHCI mode, but I cannot see the NVMe Drives in Intel Rapid Storage Technology when they are in AHCI mode (because they're NVME PCIe drives that are designed to be used in RAID mode, not AHCI). So if I wanted to set up the SSD's in RAID 1 again I can't do it and keep my data by using the Intel RST.

If I switch Windows to Safe Boot from MSCONFIG and restart and change the Controller Mode to RAID I get the XMG Logo with the spinning circle for longer than it normally takes to boot, and then it pauses for a few seconds before going back to the beginning of the boot sequence as through you hit the restart button.

I had an issue with the Intel Extreme Tunrup Utility last year and Windows wouldn't boot afterwards, I couldn't figure out how to access the BIOS so I ended up pulling the CMOS Battery which reset to AHCI from RAID but back then I got INACCESSIBLE_BOOT_DEVICE" now I don't even get that, just an attempt to boot then restart.

I tried using a bootable USB stick created with the Media Creation Tool but it cannot see the NVMe Drives when set to RAID, only the two SATA HDDs that I also have. I believe it is also nigh on impossible to get the Recovery Environment to load RAID drivers as well as or instead of AHCI.

I'm at a loss as to what I can actually do to get these drives back in RAID mode so everything is as it should be, as the old registry tweaks (such as HKLM\SYSTEM\CurrentControlSet\Services\msahci) are no longer present in Windows 10 and the ones suggested for Windows 8 such as StartOverride for "iaStorAV" don't seem to be working either.

I am not trying to create a RAID Array, I am trying to get Windows to boot with the SATA Controller set to RAID mode instead of AHCI.

My reason for wanting RAID instead of AHCI is because the Intel Rapid Storage Technology Software does not recognise the NVMe Drives under AHCI, only under RAID mode.

There is no "CTRL + I" screen for my Laptop and no Intel screen, you can create a RAID Array directly from the Intel RST settings in the BIOS.

When I purchased my Laptop I asked for the two NVMe Drives to be in RAID 1. When I had issues with Windows refusing to boot because I messed up the BIOS using the Intel Extreme Tuneup Utility I had to pull the BIOS Battery. This resulted in the BIOS changing to AHCI mode and Windows gave "INACCESSIBLE_BOOT_DEVICE".

Once I changed the Controller mode back to RAID Windows booted fine off one of the NVME drives as the RAID Array had been broken by me removing the BIOS Battery. However with the BIOS in RAID Mode I was able to see the NVMe Drives in Intel RST and I could then setup the RAID 1 Array from within Windows again and copy the data from the drive that it had booted to.

Earlier this year I decided I wanted to use the second NVMe drive for storage, and I went into the BIOS and deleted the RAID Array and set both drives back to Non-RAID. If I remember correctly I believe I still had the BIOS in RAID Mode and I could still see the NVMe drives in Intel RST in Windows. Now I cannot boot in RAID mode because I get the XMG Logo with spinning circle for longer than it normally takes to boot, then it restarts from the beginning again.

Hi,
@SergeantSteve: on my machines the raid volume needs to be created from within UEFI/BIOS first. Controller set to RAID as well.
When you install W10 you need to feed it the Intel RST driver and if you like Samsung's NVMe driver too.

Cheers,