INACCESSIBLE_BOOT_DEVICE BSOD: Bootloaders Storage Drivers and Recovery Steps

Introduction

The Windows stop code INACCESSIBLE_BOOT_DEVICE is a Blue Screen of Death (BSOD) that typically appears during startup, often immediately after a Windows update, driver change, BIOS/UEFI change, or a hardware swap. It means Windows can’t access the system partition to continue booting. It’s critical to fix promptly because it prevents you from reaching the desktop and can indicate storage driver or bootloader problems that may worsen if ignored.

This guide goes beyond generic advice. You’ll get step-by-step troubleshooting from easy to advanced, with a focus on bootloaders, storage drivers, and recovery steps. We also cover minidump analysis, Driver Verifier, Event Viewer, and when to seek professional help.

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Understanding the Error

The INACCESSIBLE_BOOT_DEVICE stop code means the Windows kernel lost access to the volume that contains the system files during the boot process. In plain language: the OS can’t talk to the disk it’s booting from.

Why this happens:

• Early in boot, Windows loads boot-start drivers for storage (e.g., storport.sys, storahci.sys, stornvme.sys, iaStorAC.sys, amdsata.sys, lsi_sas.sys, nvme.sys). If the right driver isn’t loaded (or is corrupted, blocked, or incompatible), the OS can’t read the boot volume.
• The bootloader (BCD/bootmgr/winload.efi) may point to the wrong partition or be corrupted.
• Firmware settings (e.g., AHCI/RAID, UEFI/Legacy, Secure Boot, TPM/BitLocker) can prevent access to the drive if they change unexpectedly.

Typical scenarios:

• After a Windows Update that changes the storage stack.
• Changing SATA mode (IDE/AHCI/RAID) or moving the drive to a different controller or PC.
• Installing or uninstalling a storage controller driver.
• Firmware (BIOS/UEFI) updates that reset settings.
• NVMe SSD not recognized due to missing vendor NVMe driver.
• BitLocker drive not unlocked in WinRE or after hardware/firmware changes.
• Failing SSD/HDD or loose/misrouted cables.

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Common Causes

Below are the most likely causes of the INACCESSIBLE_BOOT_DEVICE BSOD and how they manifest.

Cause	Symptoms/Notes	How to Check
Storage driver mismatch or corruption (AHCI/RAID/NVMe)	BSOD right after logo; occurred after driver update or moving disk	Safe Mode, Device Manager, minidumps (WinDbg/BlueScreenView)
Windows Update changed boot-start drivers	Started after cumulative update	DISM package history, uninstall last updates
BIOS/UEFI changes (AHCI/RAID, UEFI/Legacy, Secure Boot)	After firmware update/reset	BIOS/UEFI setup; confirm SATA mode and boot mode
BCD/bootloader corruption	“No boot device” or BSOD loop	WinRE bootrec/bcdboot; check EFI partition
Disk/SSD failures or cable issues	Random freezes, S.M.A.R.T. warnings	CHKDSK, vendor SSD tools, swap cables/ports
BitLocker not unlocked or key needed	Requests recovery key; drive locked in WinRE	manage-bde status; unlock with key
Filter drivers (antivirus/encryption) blocking storage stack	Third-party AV or encryption recently changed	Safe Mode, uninstall tools, clean boot
Malware or rootkit affecting boot chain	Suspicious modifications	Offline scan with Defender or vendor tools
RAM errors causing filesystem/driver corruption	Random BSODs beyond storage	Memory Diagnostic, MemTest86
Virtualization/VM misconfig (controller type changed)	After switching virtual disk controller	Set correct virtual controller/driver

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Preliminary Checks

Before deep-dive repairs, perform these quick checks to save time and data.

1. Boot to Safe Mode (if possible)

• Force Windows Recovery Environment (WinRE):
  • Power on, then force shutdown at the spinning dots. Repeat 3 times to trigger Automatic Repair.
  • Or boot from a Windows 10/11 installation USB and click Repair your computer.
• In WinRE: Troubleshoot > Advanced options > Startup Settings > Restart > Press 4 (Safe Mode) or 5 (Safe Mode with Networking).
• If Safe Mode works, the issue is likely a driver or service that loads normally but not in Safe Mode.

2. Back up important data now

• From Safe Mode or WinRE, copy files to an external drive.
• In WinRE, use Command Prompt to copy data or the “Open” dialog trick (e.g., Notepad > File > Open > browse and copy).
• Consider mounting the drive on another PC if necessary.

3. Run basic health checks

• CHKDSK on the system drive (from Safe Mode or WinRE):

chkdsk C: /f /r

• System File Checker:

sfc /scannow

• Deployment Image Servicing and Management:

DISM /Online /Cleanup-Image /RestoreHealth

Note: In WinRE (offline), use the offline variants provided later.

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Step-by-Step Troubleshooting

Follow these in order, from simplest to most advanced. After each step, try to boot normally.

1. Undo recent changes

• If this started after a driver or app installation, boot to Safe Mode and uninstall it.
• Roll back Windows Updates:
  • Settings > Windows Update > Update history > Uninstall updates.
  • If you cannot boot: use DISM offline (see Step 9).

2. Check physical connections and ports

• Reseat SATA power/data cables; try a different SATA port.
• For M.2 NVMe, remove and reseat. Verify it’s in the correct slot and not sharing lanes with disabled ports.
• If using an adapter or RAID card, verify power and seating.

3. Verify BIOS/UEFI settings

• Confirm SATA Mode matches what Windows expects:
  • If you installed Windows in AHCI, don’t switch to RAID or IDE and vice versa.
  • If you must change, be ready to load the correct driver in Windows later.
• Confirm Boot Mode: If Windows was installed in UEFI, keep UEFI enabled with a GPT disk. For Legacy/CSM, keep MBR and Legacy.
• Check Secure Boot status; toggling might affect boot if bootloaders or drivers are unsigned.
• If you recently updated firmware, check whether settings were reset.

4. Try Safe Mode driver correction

• Boot Safe Mode > Device Manager > Storage controllers.
• For SATA/AHCI issues:
  • Right-click controller (e.g., Intel, AMD). Choose Update driver > Browse > Let me pick > select Standard SATA AHCI Controller (Microsoft) if vendor driver is failing. Reboot.
• For NVMe:
  • If vendor driver failed, try Microsoft stornvme by uninstalling the vendor driver and rebooting; or install the vendor’s latest NVMe driver from manufacturer.
• For RAID:
  • Ensure the correct Intel RST (iaStorAC.sys) or vendor RAID driver is installed and up to date.

5. System Restore

• If you had restore points:
  • WinRE > Troubleshoot > Advanced options > System Restore > pick a restore point from before the issue.
  • This reverses drivers, registry changes, and some updates.

6. Repair bootloader (BCD/EFI)

• Boot into WinRE > Troubleshoot > Advanced options > Command Prompt.
• Identify your Windows drive letter (in WinRE letters often shift). Try:

dir C:
dir D:
dir E:

Look for a Windows folder.

• Run classic boot repair:

bootrec /fixmbr
bootrec /fixboot
bootrec /scanos
bootrec /rebuildbcd

• If “Access is denied” on /fixboot (common on Windows 10/11 UEFI):
  • Use DiskPart to assign a letter to the EFI System Partition (ESP), then rebuild boot files:

diskpart
list disk
select disk 0
list vol
select vol
assign letter=S
exit
bcdboot C:\Windows /s S: /f UEFI

• For Legacy/MBR systems:

bootsect /nt60 sys

Then reboot.

7. Run CHKDSK thoroughly from WinRE

• From Command Prompt:

chkdsk C: /f /r /x

• Replace C: with your system drive letter as seen in WinRE.

8. Run SFC and DISM offline (WinRE)

• Find your Windows drive (assume it is D: in WinRE) and the Windows installation media drive (assume X:).
• Offline SFC:

sfc /scannow /offbootdir=D:\ /offwindir=D:\Windows

• Offline DISM with local Windows files only:

DISM /Image:D:\ /Cleanup-Image /RestoreHealth

• If DISM needs source files, point it to install.wim on your USB:

DISM /Image:D:\ /Cleanup-Image /RestoreHealth /Source:WIM:X:\sources\install.wim:1 /LimitAccess

Note: The index (:1) may vary by edition; use:

DISM /Get-WimInfo /WimFile:X:\sources\install.wim

9. Uninstall the last problematic Windows update (offline)

• List packages:

DISM /Image:D:\ /Get-Packages /Format:Table

• Identify the recent KB or the package installed around the failure.
• Remove it:

DISM /Image:D:\ /Remove-Package /PackageName:Package_for_KBXXXXXX~31bf3856ad364e35~amd64~~10.0.1.0

• Reboot after removal.

10. Fix storage driver load issues offline

• If Windows can’t see the disk due to missing driver, load it in WinRE:
  • Place the correct storage driver INF files on a USB drive (from OEM).
  • Use drvload to load the INF:

drvload X:\path\to\driver.inf

• Or add and install the driver to the offline image:

pnputil /add-driver X:\path\to\driver.inf /install

• After loading, verify the Windows volume is now accessible (dir commands) and try to reboot.

11. BitLocker considerations

• If BitLocker is enabled, you may need to unlock before running repairs:

manage-bde -status
manage-bde -unlock C: -RecoveryPassword
manage-bde -protectors -disable C:

• Re-enable protection after repairs:

manage-bde -protectors -enable C:

12. Clean boot of storage stack and filters

• In Safe Mode:
  • Uninstall third-party antivirus, disk encryption, or storage filter software that adds UpperFilters/LowerFilters entries.
  • For advanced users: check registry (back up first!):
    • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class{4d36e96a-e325-11ce-bfc1-08002be10318} (DiskDrive)
    • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\<storport/storahci/iaStorAC/etc.>
  • Remove problematic filter entries only if you are certain; then reboot.

13. Update or rollback storage controller drivers

• In Safe Mode > Device Manager:
  • For Intel systems with RAID/RST, install/rollback Intel RST from the motherboard/OEM.
  • For AMD chipsets, update AMD SATA/RAID drivers.
  • For NVMe SSDs, try vendor driver (Samsung, WD) or fallback to Microsoft stornvme.
  • If the BSOD started after a driver update, use Roll Back Driver.

14. BIOS/UEFI updates and resets

• If none of the above resolves it and hardware is healthy:
  • Update BIOS/UEFI to a stable version from the OEM.
  • If you updated right before the issue, consider downgrading to the previous version.
  • Verify support settings (AHCI/RAID, PCIe/NVMe, CSM) match your Windows installation.

15. Memory test

• Faulty RAM can corrupt drivers/files:
  • Run Windows Memory Diagnostic:
    • mdsched.exe > Restart now and check for problems.
  • For thorough testing, use MemTest86 from a bootable USB.

16. In-place repair upgrade (keeps files and apps)

• If you can boot into the desktop (even Safe Mode with Networking), perform an in-place upgrade repair:
  • Download the latest Windows ISO (same edition/language).
  • Mount ISO > run setup.exe > choose Keep personal files and apps.
• If you cannot boot at all, this option isn’t available. Consider reinstall after data backup.

17. Full backup and clean install (last resort)

• If the disk is healthy but software fixes fail, back up and perform a clean Windows install.
• Recreate RAID arrays only if needed and ensure drivers are on-hand during setup.

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Minidump Analysis: Identify Faulty Drivers or Modules

If Windows creates a minidump at crash, you can pinpoint the module causing INACCESSIBLE_BOOT_DEVICE.

How to enable and locate minidumps:

• By default, Windows writes Small memory dump (256 KB) files to:
  • C:\Windows\Minidump
• Confirm or enable:
  • Control Panel > System > Advanced system settings > Startup and Recovery > Settings > Write debugging information: Small memory dump (256 KB).
• Registry (advanced):
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CrashControl
  • Ensure CrashDumpEnabled = 3 (small dump).

Tools:

• BlueScreenView or WhoCrashed: Quick, user-friendly.
• WinDbg (Preview): Deep analysis from Microsoft Store.

Basic WinDbg workflow:

1. Open dump: File > Open Crash Dump > select latest file in C:\Windows\Minidump.
2. Run:

!analyze -v
lm t n

3. Look for MODULE_NAME or IMAGE_NAME referencing storage or boot drivers:
   • storport.sys, storahci.sys, stornvme.sys, iaStorAC.sys, amdsata.sys, nvme.sys, classpnp.sys.
4. If a third-party driver is implicated (e.g., antivirus filter), uninstall or update it.

Note: Minidumps may not be created if the crash happens very early. In that case, rely on WinRE logs and Event Viewer once you can boot.

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Advanced Diagnostics

Use these tools to pinpoint root causes when initial steps don’t reveal the culprit.

1. Driver Verifier (caution: can cause additional BSODs)

• Purpose: stress-test drivers to expose faulty ones.
• Enable (run as admin):

verifier /standard /all

• Reboot and use the system; if BSODs occur, the dump should name the bad driver.
• Disable:

verifier /reset

• Only enable when you can boot and are prepared to analyze dumps.

2. Event Viewer

• Check:
  • System logs for Disk, Ntfs, storahci, iaStorAC, stornvme warnings/errors (IDs 51, 129, 153).
  • Kernel-Boot and Kernel-PnP entries around the time of failure.
• Look for “Reset to device, \Device\RaidPort0, was issued” or timeout events indicating controller/firmware issues.

3. Boot log

• Enable boot log:

bcdedit /set {current} bootlog Yes

• Reboot; check C:\Windows\ntbtlog.txt for drivers not loaded.

4. SetupDiag (for update-induced failures)

• Download Microsoft SetupDiag and run to analyze upgrade/update logs. It can highlight driver and compatibility blockers.

5. Storage health checks

• Use vendor tools (Samsung Magician, Intel MAS, WD Dashboard) to read S.M.A.R.T. and run diagnostics.
• If any reallocated sectors, pending sectors, or media errors appear, replace the drive.

6. Offline malware scanning

• Use Windows Defender Offline or vendor bootable AV scanners to rule out bootkits/rootkits affecting the boot chain.

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When to Seek Professional Help

Consider professional repair or hardware replacement when:

• The disk shows signs of failing (bad S.M.A.R.T., frequent read errors, loud clicking).
• You cannot locate or install the correct RAID/NVMe drivers and the system hosts critical data.
• The EFI/BCD keeps corrupting or the file system is severely damaged.
• Multiple BSODs implicate different low-level components (possible motherboard/controller issue).
• You need data recovery from a failing drive; DIY attempts may worsen damage.

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Prevention Tips

• Keep a stable baseline:
  • Use vendor-provided storage drivers (Intel RST/AMD/NVMe) when required by your hardware; otherwise, stick to Microsoft storahci/stornvme for simplicity.
• Update carefully:
  • Defer major Windows updates on production machines; create a restore point or image backup first.
• Firmware hygiene:
  • Update BIOS/UEFI and SSD firmware only when needed; document and re-apply critical settings (AHCI/RAID, UEFI/Legacy).
• BitLocker best practices:
  • Suspend BitLocker before firmware or hardware changes.
  • Keep recovery keys stored safely.
• Backup strategy:
  • Maintain regular system images and file backups (e.g., Windows Backup, Macrium Reflect, Veeam).
• Hardware checks:
  • Periodically check S.M.A.R.T. status and run vendor diagnostics.
  • Use quality cables, and avoid unnecessary controller swaps.
• Minimize low-level filter drivers:
  • Avoid stacking multiple third-party antivirus/encryption/filter drivers; stick to reputable, well-supported solutions.

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Conclusion

The INACCESSIBLE_BOOT_DEVICE BSOD usually traces back to a storage driver mismatch, bootloader/BCD issue, or firmware setting change. Start with Safe Mode, backups, CHKDSK/SFC/DISM, and rollbacks. Progress to fixing the bootloader, loading the correct AHCI/RAID/NVMe drivers, and leveraging System Restore. Use WinDbg, Driver Verifier, and Event Viewer for deeper analysis. With methodical steps, most systems can be recovered without data loss.

Take your time, make one change at a time, and document what you try. With the right approach, this BSOD is usually fixable.

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FAQ Section

Can I ignore the INACCESSIBLE_BOOT_DEVICE BSOD and keep using my PC?

No. This error prevents Windows from booting normally. It indicates a critical problem with storage access or boot configuration that must be fixed before the system can start.

Does this BSOD mean my SSD or HDD is failing?

Not necessarily. Many cases are due to driver or firmware changes. However, run CHKDSK and vendor diagnostics to rule out hardware failure.

I changed BIOS from AHCI to RAID (or vice versa). Is that the cause?

Very likely. Windows expects the same controller mode it was installed with. Switch back to the original mode or install the correct driver for the new mode.

Will reinstalling Windows always fix it?

A clean install usually works but is a last resort. Try the steps in this guide first: repair bootloader, fix storage drivers, rollback updates, and use System Restore. Always back up data before reinstalling.

I get “Access is denied” on bootrec /fixboot. What should I do?

Assign a letter to the EFI System Partition with DiskPart and rebuild the boot files using:
bcdboot C:\Windows /s S: /f UEFI

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Appendix: Quick Command Reference

• Safe Mode (WinRE): Troubleshoot > Advanced options > Startup Settings > Restart > 4/5/6 keys.
• CHKDSK:

chkdsk C: /f /r /x

• SFC online:

sfc /scannow

• DISM online:

DISM /Online /Cleanup-Image /RestoreHealth

• SFC offline:

sfc /scannow /offbootdir=D:\ /offwindir=D:\Windows

• DISM offline with media:

DISM /Image:D:\ /Cleanup-Image /RestoreHealth /Source:WIM:X:\sources\install.wim:1 /LimitAccess

• Boot repair (UEFI):

diskpart
list vol
select vol
assign letter=S
exit
bcdboot C:\Windows /s S: /f UEFI

• Driver Verifier:

verifier /standard /all
verifier /reset

• BitLocker:

manage-bde -status
manage-bde -unlock C: -RecoveryPassword
manage-bde -protectors -disable C:
manage-bde -protectors -enable C:

Stay patient and systematic. With these bootloader, storage driver, and recovery steps, you’re well-equipped to resolve the INACCESSIBLE_BOOT_DEVICE BSOD.