Windows Boot Manager fails to start [Request Assistance].
Windows Boot Manager fails to start [Request Assistance].
I saved the manual for your mainboard and followed these steps: In BIOS, press F7 to enter Advanced Mode. Navigate to the Advanced tab and choose SATA Configuration, selecting AHCI. Save changes and exit. Then restart and go back to BIOS. In the Boot section, list your HDD as the first boot device according to priority options. You mentioned not seeing CSM in BIOS—possibly the manual contains an error or your board is outdated. There’s no UEFI setup visible except in RAID mode. It seems the BIOS might be strange or incorrect. If you lose data, it’s unlikely; you can verify by creating a bootable Ubuntu USB on another machine. Avoid formatting the drive and don’t alter the Windows installation—your important files are safest preserved.
Enable UEFI only, apply changes, restart BIOS, disable CSM, save again, re-enter BIOS, configure HDD as primary boot, turn off secure boot, save and start. If unsure, switch to USB in this mode and fix the boot process using Windows 10 without reinstalling.