Quick Summary
The error code 0x0000007B, also known as INACCESSIBLE_BOOT_DEVICE, typically indicates that Windows has lost access to the system partition during startup. This usually happens because the boot device (e.g., hard drive or SSD) or the drivers required to access it are not available to the operating system during the boot process.
Common Causes
- Incorrect Boot Order in BIOS: The BIOS might be configured to boot from a different device than the one containing the Windows installation. This can occur after hardware changes or BIOS updates.
- Corrupted Boot Sector or Master Boot Record (MBR): The boot sector or MBR on the hard drive could be damaged due to malware, disk errors, or improper shutdowns. A corrupted MBR will prevent the system from locating the operating system.
- Driver Issues (Storage Controller Drivers): The drivers for the storage controller (e.g., SATA or IDE controller) might be missing, corrupted, or incompatible with the installed operating system. This is particularly common when migrating a hard drive from one system to another with different hardware configurations.
- Hardware Problems (Hard Drive or SSD): The hard drive or SSD containing the operating system might be physically damaged or failing. Cables might be loose, or the drive itself might be experiencing internal errors.
- File System Corruption: The NTFS/FAT32 file system on the boot volume may be corrupted, preventing proper access to system files needed for booting.
Step-by-Step Fixes
Method 1: Check the Boot Order in BIOS/UEFI
Step 1: Restart your computer and enter the BIOS/UEFI setup. The key to press is usually displayed on the screen during startup (e.g., Delete, F2, F12, Esc).
Step 2: Navigate to the 'Boot Order' or 'Boot Priority' section.
Step 3: Ensure that the hard drive or SSD containing your Windows installation is listed as the first boot device.
Step 4: Save the changes and exit the BIOS/UEFI setup. The computer will restart automatically.
Method 2: Run Startup Repair from Windows Recovery Environment
Step 1: Boot from a Windows installation media (DVD or USB). If you don't have one, you'll need to create one using another working computer, downloading the Media Creation Tool from Microsoft's website.
Step 2: Select your language preferences and click 'Next'.
Step 3: On the next screen, click 'Repair your computer'.
Step 4: Choose 'Troubleshoot', then 'Advanced options', and finally select 'Startup Repair'.
Step 5: Select the operating system you want to repair. Startup Repair will automatically scan and attempt to fix boot-related issues.
Method 3: Check Disk using Command Prompt in Recovery Environment
Step 1: Boot from Windows installation media and navigate to the 'Advanced options' screen as described in the 'Startup Repair' section above.
Step 2: Select 'Command Prompt'.
Step 3: Type chkdsk /r C: and press Enter. Replace 'C:' with the drive letter containing your Windows installation if it is different.
Step 4: Press 'Y' if prompted to schedule the disk check to run at the next system restart.
Step 5: Restart your computer. The Check Disk utility will scan and attempt to repair errors on your hard drive.
Method 4: Rebuild the Boot Configuration Data (BCD)
Step 1: Boot from Windows installation media and open the Command Prompt from the Recovery Environment (as described above).
Step 2: Type the following commands, pressing Enter after each one:
bootrec /fixmbr
bootrec /fixboot
bootrec /scanos
bootrec /rebuildbcd
Step 3: If bootrec /scanos identifies any Windows installations, you will be prompted on whether to add them to boot list, type Y for yes and press Enter.
Step 4: Restart your computer.
Method 5: Update or Reinstall Storage Controller Drivers
Step 1: Determine the make and model of your storage controller (e.g., SATA controller).
Step 2: If you can boot into safe mode (typically by pressing F8 repeatedly during startup), try to update the storage controller drivers from Device Manager. Press Windows Key + R, type devmgmt.msc, and press Enter. Expand 'IDE ATA/ATAPI controllers' or 'Storage controllers'. Right-click the controller and select 'Update driver'. If this fails, try uninstalling the device then restart the PC.
Step 3: Otherwise, use a separate computer to download the latest drivers for your storage controller from the manufacturer's website (e.g., Intel, AMD, Marvell).
Step 4: Transfer the drivers to a USB drive, boot from the USB drive, and follow the manufacturer's instructions for installing the drivers.