Computer Blue Screen on Startup Windows 10: Complete Fix Guide (BSOD at Boot)

Understanding the Windows 10 Blue Screen on Startup

A Blue Screen of Death (BSOD) that appears on every startup — before or during the Windows 10 loading animation — is one of the most disruptive failure modes a PC can experience. Unlike BSODs that occur during normal use, a boot-time BSOD creates a loop where Windows cannot load far enough to let you fix the problem through the normal interface. This guide walks you through every layer of diagnosis and repair.

Common BSOD stop codes you may see on the blue screen include:

• INACCESSIBLE_BOOT_DEVICE (0x0000007B)
• CRITICAL_PROCESS_DIED (0x000000EF)
• UNMOUNTABLE_BOOT_VOLUME (0xC000009A)
• SYSTEM_THREAD_EXCEPTION_NOT_HANDLED (0x0000007E)
• MEMORY_MANAGEMENT (0x0000001A)
• KERNEL_SECURITY_CHECK_FAILURE (0x00000139)
• PAGE_FAULT_IN_NONPAGED_AREA (0x00000050)
• BAD_SYSTEM_CONFIG_INFO (0x00000074)

On Dell computers, BSOD on startup in Windows 10 is frequently linked to SupportAssist pre-installed drivers, Intel RST (Rapid Storage Technology) driver mismatches, or BIOS settings like Secure Boot or SATA mode (AHCI vs RAID) conflicting with the OS. On new computers, the culprit is often that the OEM image shipped with an older driver set incompatible with the current hardware revision or Windows 10 feature update.

Phase 1: Identify the Stop Code and Entry Point

Before applying any fix, capture the exact stop code:

1. Allow the BSOD to display fully. Windows 10 shows a QR code and a stop code at the bottom of the blue screen (e.g., INACCESSIBLE_BOOT_DEVICE).
2. If the system reboots too quickly, interrupt boot three times in a row by holding the power button during POST. This forces Windows into Automatic Repair mode.
3. Alternatively, press F8 or Shift+F8 during boot (works on BIOS/legacy systems; may not work on UEFI fast-boot systems) to access Advanced Boot Options.
4. If you have a Windows 10 installation USB, boot from it, choose "Repair your computer," then navigate to Troubleshoot > Advanced Options > Command Prompt.

Phase 2: Run Windows Startup Repair

This is always your first stop. From WinRE (Windows Recovery Environment):

Troubleshoot → Advanced Options → Startup Repair

Windows will automatically attempt to fix boot configuration issues. Let it complete fully. If it succeeds, reboot and test. If it fails with the message "Startup Repair couldn't repair your PC," proceed to Phase 3.

Phase 3: Repair System Files with SFC and DISM

If you can reach Safe Mode (press F4 at the boot options screen) or a Command Prompt via WinRE:

Step 3a — System File Checker:

sfc /scannow

SFC scans all protected Windows system files and replaces corrupted versions with cached copies. If run from WinRE, you must specify the Windows volume:

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

Look for the result message: "Windows Resource Protection found corrupt files and successfully repaired them" or "could not perform the requested operation" (the latter means DISM is needed first).

Step 3b — DISM RestoreHealth:

Dism /Online /Cleanup-Image /RestoreHealth

DISM downloads replacement files from Windows Update to repair the component store. If the system cannot reach the internet, mount your Windows 10 ISO and point DISM to it:

Dism /Online /Cleanup-Image /RestoreHealth /Source:wim:D:\sources\install.wim:1 /LimitAccess

After DISM completes, run SFC again and then reboot.

Phase 4: Rebuild the Boot Configuration Database (BCD)

For INACCESSIBLE_BOOT_DEVICE, BAD_SYSTEM_CONFIG_INFO, or any error suggesting Windows cannot find the boot drive:

From WinRE Command Prompt:

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

If bootrec /fixboot returns "Access is denied," the EFI partition is locked. Unlock it first:

diskpart
list disk
sel disk 0
list vol
sel vol <EFI volume number>
assign letter=Z:
exit
bcdboot C:\Windows /s Z: /f UEFI

Reboot after completing these steps.

Phase 5: Check and Fix the Boot Drive

For UNMOUNTABLE_BOOT_VOLUME or disk-related codes:

chkdsk C: /f /r /x

The /r flag locates bad sectors and recovers readable data. This can take 1–2 hours on large drives. Let it complete without interruption.

Also verify drive health using CrystalDiskInfo (bootable tools like Hiren's BootCD include it). Look for Reallocated Sectors Count or Pending Sector Count — any non-zero values on these SMART attributes indicate physical drive failure requiring replacement.

Phase 6: Address Driver Issues (Critical for Dell and New PCs)

If the BSOD started after a Windows Update or driver installation:

1. Boot into Safe Mode (F4 at boot options).
2. Open Device Manager (devmgmt.msc).
3. Look for any device with a yellow warning triangle.
4. For Dell systems, check: IDE ATA/ATAPI controllers → Intel RST driver. If it shows version mismatch, right-click → Update driver → Browse locally → use the driver downloaded from Dell's support site.
5. For GPU drivers (common cause of SYSTEM_THREAD_EXCEPTION_NOT_HANDLED): uninstall the current display adapter driver via Device Manager, then use DDU (Display Driver Uninstaller) in Safe Mode for a clean removal before installing the latest driver from NVIDIA/AMD/Intel.
6. To roll back a driver: Device Manager → right-click device → Properties → Driver tab → Roll Back Driver.

For Dell BIOS SATA Mode conflicts:

• Enter BIOS (F2 at boot) → Advanced → SATA Operation
• If set to RAID, change to AHCI (note: this will cause a BSOD if Windows was installed in RAID mode; only change if you know the original install mode)
• A safer method: boot to Safe Mode first, enable AHCI via registry, then change BIOS setting

Phase 7: Test RAM

From WinRE: Troubleshoot → Advanced Options → Windows Memory Diagnostic (schedules a test on next boot).

For thorough testing, boot MemTest86 from USB and run at least 2 full passes. If errors appear, reseat the RAM sticks first (remove, clean gold contacts with eraser, reinsert). If errors persist on a specific stick, replace it.

Phase 8: System Restore or Reset

If a restore point exists from before the BSOD began: WinRE → Troubleshoot → Advanced Options → System Restore

As a last resort before hardware replacement: WinRE → Troubleshoot → Reset this PC → Keep my files (or Remove everything for a clean slate)

For truly persistent cases on new computers, download a fresh Windows 10 ISO from Microsoft using the Media Creation Tool and perform a clean install after confirming hardware health.