Changing from AHCI to RAID causes boot loop


  1. Posts : 6
    Windows 10
       #1

    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.
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  2. Caledon Ken's Avatar
    Posts : 24,255
    Windows 10 Pro x64 Version 2004
       #2

    Hi SergeantSteve.

    When you boot from from the media created with the media creation tool, and you already have the BIOS set to raid, do you create the raid when you see the Intel screen. You have to enter the software, CRTL + I, during the boot, before windows installation starts and create Raid. At least that is how I remember doing it.

    Maybe that is what you are doing but thought I would confirm.
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  3. Posts : 6
    Windows 10
    Thread Starter
       #3

    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.
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  4. Caledon Ken's Avatar
    Posts : 24,255
    Windows 10 Pro x64 Version 2004
       #4

    Okay but why not repeat what "worked" before. Create the the raid 1 array using both drives boot, install windows and then break array.

    Have a look at this tutorial, in particular step 12. You may have to load drivers as part of the installation.

    Clean Install Windows 10
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  5. Posts : 2,764
    Windows 10 Pro X64
       #5

    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,
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  6. spunk's Avatar
    Posts : 2,844
    Windows 10 Pro 64 Bit 20H2
       #6

    When you change the HDD mode from AHCI to RAID, you have to reinstall the OS from scratch. You may be able to edit the Windows Registry to accept the change. Be sure to backup the registry and your files before attempting. How to: Change SATA Modes After Windows Installation
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  7. Posts : 1
    Windows 10
       #7

    This is the top search result for this issue, so I'm resurrecting it for anyone who comes across this thread in the future. The fix for boot loop in Windows 10 after switching from AHCI to RAID mode:

    - Switch back to AHCI mode in BIOS (in order to break the boot loop and get back into Windows).
    - Use msconfig to enable safe boot (Windows Key + R, msconfig, Boot tab, Safe boot), then restart.
    - Upon this restart enter BIOS settings and switch to RAID mode, exit and save.
    - Boot into Windows (safe boot), use msconfig to disable safe boot, then restart.

    Windows will now boot normally under RAID mode.
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  8. jimbo45's Avatar
    Posts : 10,491
    Windows / Linux : Arch Linux
       #8

    Hi there
    domestic (i.e consumer grade RAID cards are usually an abomination). On Windows until a decent software solution (like Linux MDADM) is found I suggest you attempt to use the nearest software equivalent on Windows -- AHCI and Storage spaces -- but AYOR.

    If you need sensible RAID then cards are expensive -- best bet is to use LINUX and run Windows as a VM. !!!!

    I've long wanted decent software RAID on Windows that is resilient and works. (Commercial enterprise RAID cards and SAS controllers are fine but they are expensive and over the top for domestic home computers).

    Cheers
    jimbo
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  9. Posts : 1
    Win10
       #9

    myninerides said:
    This is the top search result for this issue, so I'm resurrecting it for anyone who comes across this thread in the future. The fix for boot loop in Windows 10 after switching from AHCI to RAID mode:

    - Switch back to AHCI mode in BIOS (in order to break the boot loop and get back into Windows).
    - Use msconfig to enable safe boot (Windows Key + R, msconfig, Boot tab, Safe boot), then restart.
    - Upon this restart enter BIOS settings and switch to RAID mode, exit and save.
    - Boot into Windows (safe boot), use msconfig to disable safe boot, then restart.

    Windows will now boot normally under RAID mode.
    Worked perfectly for me, thanks!

    FWIW, this was a Dell Poweredge T5810 that I added two new HDDs to for RAID and the OS was already on an SSD. Tried to regedit the OS from recovery but keys were missing. Safe mode trick worked a treat.
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  10. Jaguwaar20's Avatar
    Posts : 74
    Windows 10 Home
       #10

    It looks by following the sequence of comments stated by the OP and what those intentions he had were, that some of the other posts missed what was more involved :
    if I remember correctly I believe I still had the BIOS in RAID Mode.
    Somehow the BIOS has been set back to AHCI...
    I am not trying to create a RAID Array. . . 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.
    Once I changed the Controller mode back to RAID Windows booted fine off one of the NVME drives.

    @myninerides commented:
    This is the top search result for this issue, so I'm resurrecting it for anyone who comes across this thread in the future. The fix for boot loop in Windows 10 after switching from AHCI to RAID mode:

    - Switch back to AHCI mode in BIOS (in order to break the boot loop and get back into Windows).
    - Use msconfig to enable safe boot (Windows Key + R, msconfig, Boot tab, Safe boot), then restart.
    - Upon this restart enter BIOS settings and switch to RAID mode, exit and save.
    - Boot into Windows (safe boot), use msconfig to disable safe boot, then restart.

    Windows will now boot normally under RAID mode.
    @nedge2k followed with a comment:
    Worked perfectly for me, thanks!
    I realize this is a dated post. IRST software driver was mentioned to the OP, but he wasn't provided how to circumvent the boot loop in Windows using IRST when changing back from AHCI to RAID mode. Getting Windows to boot using Intel's RST driver in RAID mode under the SATA Controller setting of the mobo BIOS is more involved than just using MSCONFIG to enable Safe boot and override the AHCI protocol.

    These steps are addressed on the attached github page:

    Switching between AHCI and RAID on the Dell XPS 15 (9560) . GitHub

    [EDIT] Some motherboards may support the SATA controller to be put in RAID mode without activating these steps listed
    Last edited by Jaguwaar20; 11 Oct 2020 at 13:09.
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