I cannot load Win 11 since auto update yesterday - goes straight to BIOS

spapakons · 2026-09-19T16:46:36-0400

Seanhunt said:
When I installed the Hyper M.2 card the PC failed to install Windows.

Change the disk boot priority in BIOS so the Windows disk is first and then the others.

Celery · 2026-09-19T18:31:35-0400

spapakons said:
Change the disk boot priority in BIOS so the Windows disk is first and then the others.

The screenshot does not show that Windows “failed to install”; it shows that the existing Windows installation failed to boot, with the UNMOUNTABLE_BOOT_VOLUME (0xED) error, which means that Windows Boot Manager got far enough to start Windows, but Windows then could not mount the boot volume.

Asus272 · 2026-09-19T18:55:20-0400

I don't know if this is helpful. I never heard of this card before.

Critical BIOS Setup

If you plug the Hyper M.2 card in and only one SSD shows up, you must manually change a setting in the ASUS UEFI BIOS: [3]

Boot into the BIOS (press Del or F2).
Switch to Advanced Mode (F7).
Navigate to Advanced > Onboard Devices Configuration.
Look for the configuration option corresponding to the slot you used (e.g., PCIEX16(G4) Configuration).
Change it from Auto to Dual M.2 SSD (which enables x4/x4 bifurcation).
Save and exit (F10). [3, 4]

spapakons · 2026-09-19T19:01:13-0400

Boot with Windows 11 Setup USB flash drive. At Setup screen press SHIFT+F10 to open a Command Prompt. Execute these commands:

Code:

bootrec /fixmbr
bootrec /fixboot
bootrec /rebuildbcd
bcdboot c:\Windows

The first might fail on a GPT disk, proceed with the rest commands.

The last is to copy the boot files. You can verify that C: is the Windows disk if you execute dir C: to see the contents. You should see Program Files and Windows folders among others. If not replace C with D, then with E until you see the Windows disk and run the bcdboot command accordingly. I am not sure if any more parameters are needed for the bcdboot command, anyone please correct syntax as appropriate.

Scannerman · 2026-09-19T20:08:36-0400

Asus272 said:
Critical BIOS Setup
If you plug the Hyper M.2 card in and only one SSD shows up, you must manually change a setting in the ASUS UEFI BIOS: [3]

Boot into the BIOS (press Del or F2).

Switch to Advanced Mode (F7).

Navigate to Advanced > Onboard Devices Configuration.

Look for the configuration option corresponding to the slot you used (e.g., PCIEX16(G4) Configuration).

Change it from Auto to Dual M.2 SSD (which enables x4/x4 bifurcation).

Save and exit (F10). [3, 4]

I think there is something to this. The card in question was specifically designed for ASUS units running NVMe in RAID (likely RAID 0). IF the OS is on the RAID array no amount of CMD will make a difference until the array is repaired first. I have been following this thread for some time now without responding to it because I've only succeeded in making RAID in NVMe work once. My daughter is quite pleased with it. That aside I am persuaded to state here that BIFURCATION is not optional and must be activated in order to run M.2 in RAID. Once this is dealt with the rest of it should fall into place quite easily, or at least that was my experience.

This is NOT to suggest that spapakons instructions are without merit. Once the array has been established those additional instructions should be followed in order to avoid the same thing happening all over again.

I hope this helps.

Celery · 2026-09-20T04:08:29-0400

spapakons said:
bootrec /fixmbr
bootrec /fixboot

The commands bootrec /fixmbr and bootrec /fixboot are relevant to the legacy BIOS/MBR boot path. They are not applicable to repairing the UEFI boot path on UEFI/GPT configurations, where the UEFI firmware loads EFI executables (.efi) directly from the EFI system partition, bypassing traditional MBR/VBR boot sector chaining.

bootrec /FixMbr

BIOS/MBR: Writes a Windows-compatible Master Boot Record (MBR) to sector 0 of the system disk. This operation overwrites the existing master boot code without modifying the existing partition table.
UEFI/GPT: The disk contains a Protective MBR in sector 0. Modifying its boot code has no effect on how Windows boots in UEFI mode.

bootrec /FixBoot

BIOS/MBR: Writes new Windows-compatible boot code to the Volume Boot Record (VBR) of the active system partition.
UEFI/GPT: The FAT32-formatted EFI system partition still has a Volume Boot Record (VBR), but its executable boot code is ignored when Windows boots in native UEFI mode.

BIOS/MBR: firmware → MBR boot code → active partition's VBR boot code → bootmgr → BCD → winload.exe
UEFI/GPT: firmware → UEFI NVRAM boot entry → bootmgfw.efi → BCD → winload.efi

spapakons said:
bootrec /rebuildbcd
bcdboot c:\Windows

OP has already successfully repaired the UEFI boot environment and BCD store using:

bcdboot C:\Windows

There is therefore no reason to run the command again at this point.

bootrec /RebuildBcd scans attached disks for Windows installations and allows detected installations to be added to the BCD store. It is not necessary before bcdboot in this case. bcdboot can itself repair the boot environment and create a BCD store from the installed Windows files.

Code:

bootrec /?

/RebuildBcd -- scan all disks for installations compatible with Windows and allow the user to choose which to add to the boot configuration store.

Code:

bcdboot /?

Bcdboot - Bcd boot file creation and repair tool.

The bcdboot.exe command-line tool is used to copy critical boot files to the
system partition and to create a new system BCD store.

bcdboot <source> [/l <locale>] [/s <volume-letter> [/f <firmware>]] [/v]
                 [/vbcd] [/m [{OS Loader ID}]] [/addlast] [/p] [/c]
                 [/nofirmwaresync] [/description <description>]

ChatGPT:

More importantly, the current UNMOUNTABLE_BOOT_VOLUME (0xED) error occurs after the UEFI boot process has progressed far enough to start loading Windows. It is therefore not evidence of a BCD boot-path problem. Running bcdboot C:\Windows again would not address the reason Windows is subsequently unable to mount its boot volume.

UNMOUNTABLE_BOOT_VOLUME (0xED) means that Windows has started loading, but the Windows kernel cannot mount the volume containing the operating system.

In other words, the firmware and Windows Boot Manager have already done enough to hand control over to Windows, but Windows then loses or cannot obtain usable access to its system volume.

Possible causes include file-system corruption, a storage-controller or storage-driver problem, a change in the way the drive is presented to Windows, or a problem with the storage device itself.

In this case, the fact that the error appears after installing the Hyper M.2 card is particularly relevant and makes a storage-path or configuration problem worth investigating.

The important distinction is:

BCD/boot-manager problem: Windows cannot get started properly.

0xED UNMOUNTABLE_BOOT_VOLUME: Windows has started loading, but cannot mount/access the volume it needs to continue booting.

PenPusher · 2026-09-20T05:16:51-0400

Have you updated the Bios? if not you are missing some important settings changes to limit overclocking problems. Latest Bios is 3202.

This will reset your Bios to default, and we can advise you to which are the best settings going forward.

If needed a backup of all your current settings can be made, and reapplied after updating, But sometimes Asus moves things around!! One new setting is to do with Intel default processor power limits!

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