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Encountering the dreaded “Unmountable Boot Volume” error on Windows 10 or 11 can bring your productivity to a halt, presenting a blue screen of death (BSOD) that prevents your system from booting properly.

Whether you’re a tech novice or an experienced user, follow these steps to fix the unmountable boot volume error and restore your computer’s functionality.

What Does “Unmountable Boot Volume” Mean?

The “Unmountable Boot Volume” error in Windows is a Blue Screen of Death (BSOD) error that occurs when your computer’s operating system is unable to read from the partition of the hard drive that contains the system files. This error can be caused by various issues, including a corrupted file system, damaged hard drive, or faulty hardware.

When you start your computer, the BIOS hands over control to the Master Boot Record (MBR) on the hard drive, which then loads the operating system. 

The Master Boot Record (MBR) is a special type of boot sector at the very beginning of partitioned computer mass storage devices like fixed disks or removable drives intended for use with IBM PC-compatible systems and beyond. The MBR holds the information on how the logical partitions, containing file systems, are organized on that medium. 

If, during this process, Windows is unable to access the system partition due to corruption or physical damage to the hard drive, it cannot load the operating system, resulting in the “Unmountable Boot Volume” error.

This error prevents Windows from starting, making it a critical issue that requires immediate attention. Solutions can range from running the Windows Automatic Repair tool, using the “chkdsk” command in the Windows Recovery Environment to check for and fix disk errors, to more drastic measures like reinstalling Windows if the issue is related to corrupted system files. In cases where the hard drive is physically damaged, replacing the hard drive might be the only solution.

Causes of “Unmountable Boot Volume” in Windows 10

The “Unmountable Boot Volume” error in Windows 10 can stem from several causes, each affecting the system’s ability to access the boot partition.

Here are the most common causes:

  • Corrupted File System: Abrupt shutdowns, power failures, or improper restarts can lead to file system corruption on the boot volume. This makes the boot volume unreadable to the operating system during startup.
  • Faulty Hard Drive: Physical damage or wear and tear on the hard disk can create bad sectors or other issues that prevent access to critical boot information. This is more common in older drives but can also occur due to physical impacts or manufacturing defects.
  • Damaged System Files: Critical system files required for booting Windows can become corrupted due to software conflicts, malware infections, or unsuccessful updates and installations, leading to this error.

Also Read: How to Find and Fix Corrupted Files in Windows 10?4

  • Faulty or Improperly Connected Hardware: Sometimes, newly installed hardware or improperly connected drives can conflict with the system’s ability to boot properly.
  • MBR (Master Boot Record) Issues: The MBR contains the information necessary to successfully boot Windows. If it’s corrupted, possibly by malware or disk errors, Windows cannot start.
  • Boot Volume Misconfiguration: Changes in the BIOS or UEFI settings related to the boot order or legacy and UEFI boot modes can cause the system to attempt to boot from the wrong volume.
  • Failed Windows Update or Driver Conflict: Occasionally, a Windows update or driver update may not complete correctly, leading to system file corruption or conflicts that result in boot issues.

Also Read: Ultimate Guide: How to Manually Check and Install Windows Updates

Understanding the underlying cause is crucial for troubleshooting the “Unmountable Boot Volume” error in Windows 11 and 10 effectively. 

How to Fix “Unmountable Boot Volume” in Windows 10/11

Fixing the “Unmountable Boot Volume” error in Windows 10 involves several troubleshooting steps. Here’s how you can address this issue:

1. Use Automatic Repair:

  • Restart your computer and boot from the Windows 10 installation media.
  • Select your language preferences, and click “Next.”
  • Click “Repair your computer” instead of “Install now.”
  • Choose “Troubleshoot” > “Advanced options” > “Startup Repair.”
  • Follow the on-screen instructions to complete the repair process.

2. Run the Check Disk Utility

Access the Advanced Startup Options menu using the Windows 10 installation media as described above.

  • Navigate to “Troubleshoot” > “Advanced options” > “Command Prompt.”
  • Type chkdsk /r c: and press Enter. Replace c: with your Windows installation drive if different.

Wait for the process to complete. This utility will attempt to fix any found errors on the disk.

3. Rebuild the Boot Configuration Data (BCD)

  • Boot from the Windows 10 installation media and open Command Prompt from the Advanced Startup Options.
  • Type the following commands, pressing Enter after each:
    • bash
    • Copy code
    • bootrec /fixmbr
    • bootrec /fixboot
    • bootrec /scanos
    • bootrec /rebuildbcd
  • After executing these commands, restart your computer.

4. Restore System to a Previous State Using System Restore

If you have a System Restore point created on your PC, you can use it to “go back in time” on your computer before you ever encountered the “Unmountable Boot Volume” error. Here’s how:

  • From the Advanced Startup Options, select “System Restore.”
  • Choose a restore point before the error started occurring.
  • Follow the prompts to restore your system.#
Keep in mind that this solution is only available if you have System Restore enabled on your PC and if you have already created one. If you don’t yet have a System Restore point on your PC, we strongly suggest you create one.

Also Read: [FIXED] System Restore Not Working in Windows 10

5. Reset Your PC

If none of the above methods work, you may need to reset your PC.

Warning
If you choose to “remove everything,” all your personal files, applications, and settings will be deleted. Even if you opt to “keep your files,” only personal files will be preserved; apps and settings will still be reset to their default state. Ensure you have backed up all important data to an external drive or cloud storage.
  • Go to “Troubleshoot” > “Reset this PC” in the Advanced Startup Options.
  • Choose whether to keep your files or remove everything.
  • Follow the instructions to reset your PC.

6. Check for Hardware Issues:

If you suspect the error is due to a failing hard drive or other hardware component you can Run a diagnostic using the manufacturer’s utility or BIOS/UEFI diagnostic tools.As an option you can run a Windows Memory Diagnostic tool t to check for memory issues:

  • In the Windows search box, type “Windows Memory Diagnostic” and select it from the results.
  • Choose “Restart now and check for problems” to run the memory test. Remember, this will immediately restart your computer, so save any open work beforehand. The tool will run before the next Windows startup and check your memory for errors, displaying the results after restarting.
  • Consider physically checking the connections or consulting with a professional for hardware repair or replacement.

Useful Reading: How to Run Hard Drive Diagnostics on Windows PC?

Before proceeding with these steps, it’s essential to back up important data if possible. If you’re unable to access your files, consider using a live Linux USB to boot and transfer your data to an external drive or another safe location. Always ensure you have a recent backup of important files to prevent data loss.

PRO TIP
When Windows fails to boot due to hardware or severe system issues, accessing your files to back them up can become impossible through normal means. A Live Linux USB provides an alternative boot environment independent of your Windows installation. This allows you to bypass the non-functional Windows OS to access the files stored on your hard drive.

Conclusion

Resolving the “Unmountable Boot Volume” error in Windows 10/11 can be straightforward with the right steps. From using Automatic Repair to running disk checks and rebuilding the boot configuration, each method offers a path to recovery.

It’s crucial to act promptly and ensure data backups to safeguard against loss. This guide arms you with the necessary tools to overcome this challenge and restore your system’s functionality efficiently.

FAQ

The error itself doesn’t cause data loss, but attempting repairs without proper precautions, like backups, can be risky. Always back up important files before troubleshooting.
No, the Automatic Repair function is designed to fix startup issues without affecting your personal files. However, it’s always wise to have backups just in case.
Some methods, like Automatic Repair, require installation media. However, Windows 10/11 often has a recovery environment pre-installed that you can access without media by interrupting the boot process three times consecutively.
If standard fixes fail, the issue might be hardware-related, such as a failing hard drive. Consider consulting with a professional or exploring hardware diagnostic tools provided by your device manufacturer.