A blue screen boot loop after a storage mode change feels like a dead Windows. It is a five-minute mismatch with a safe way back — and the first step is simply undoing the change.
You changed the BIOS storage mode — RAID On to AHCI, or VMD off — and now the PC that worked yesterday blue-screens with INACCESSIBLE_BOOT_DEVICE and restarts in a loop. Stop. Do not reinstall Windows, do not run random repair tools. The recovery order is short, safe, and starts with the move most people never try: put the setting back.
This works because Windows was never broken. It holds the driver for the old mode; give it the old mode back and the boot succeeds. Automatic repair and Startup Repair cannot fix this, because the repair environment faces the same missing driver.
Now that Windows is alive again and you know the return path works, follow the safe order from this series: run bcdedit /set {current} safeboot minimal in an administrator Command Prompt, restart into BIOS, change the mode to AHCI or VMD off, boot into Safe Mode once, then run bcdedit /deletevalue {current} safeboot and restart. Five minutes, no loop, no reinstall.
There are only two or three positions the switch can be in. Try them one at a time — RAID On / VMD Enabled, then AHCI — booting after each. One of them is the mode Windows was installed under, and that attempt will boot. Avoid changing unrelated BIOS settings while you search; every extra change adds a variable you cannot account for later.
Then the mode change is probably not the whole story. Consider: a BitLocker recovery screen means the key, not a reinstall, is the answer — firmware changes legitimately trigger it. A PC that fails identically in every mode, with the drive missing in BIOS, has the hardware problem covered in the dead-drive test of this series. Only when the drive is visible, the mode is original, and Windows still cannot start should you move to WinRE repairs like System Restore — in that order, and not before.
After you recover the boot, watch the video to complete the original job — a Windows install that can actually see the drive.
▶️ Watch Full VideoBecause Windows boots using the storage driver for the mode it was installed under. Change the mode without preparing, and at boot it searches for the old controller, cannot find its own disk, and stops with INACCESSIBLE_BOOT_DEVICE. The Windows installation itself is undamaged.
Startup Repair cannot — the repair environment has the same driver problem. System Restore does not change which storage driver loads at boot either. The reliable fix is restoring the original BIOS storage mode so Windows boots, then switching modes properly with the safeboot preparation described in this series.
Yes, and now you have proof the return path works. This time prepare Windows first: bcdedit safeboot minimal, restart into BIOS, change the mode, boot Safe Mode once, delete the safeboot value, and restart. That order lets Windows adopt the AHCI driver instead of crashing against it.