How to Fix an Unmountable Boot Volume in Windows 10?

Boot Volume is a hard drive partition that stores both, the boot files and the Windows system. At times, while booting in Windows 10, you might have come across the “UNMOUNTABLE_BOOT_VOLUME” error resulting in a BSOD and keeps you from getting into Windows. The error can be tricky to deal; however, now impossible to solve as well.

If you are stuck with the “UNMOUNTABLE_BOOT_VOLUME” error and cannot find any solution for it, then you have landed into the right place. Today, within this article, we will discuss the reasons behind the said error occurrence and will discuss various possible solutions that will help you in getting rid of them quickly. Let’s learn more.

Reasons that trigger the “UNMOUNTABLE_BOOT_VOLUME” error

There are several reasons behind the “UNMOUNTABLE_BOOT_VOLUME” error. Anyway, here we have listed some of the common reasons:

Corrupt system files
Corrupt files on the hard disk
A major Windows 10 update
Damaged hard disk or RAM
If BIOS is modified manually (improperly off course), the wrong configuration can also be one reason. Though only in some rare cases.

Methods to Fix UNMOUNTABLE_BOOT_VOLUME error

Try the fixes mentioned below:

FIX 1: Use Windows Automatic Repair:

Using the Windows Automatic repair feature would help you in getting rid of the “UNMOUNTABLE_BOOT_VOLUME” error. However, as obvious, you cannot boot the Windows normally, it is recommended that you use a bootable USB drive or a Windows installation disc for accessing the Windows’ troubleshooting tool. For doing so,

Firstly, insert the Windows installation disc and then press the Power button simultaneously.
Once your system starts to boot, press a key (F8, F9, F12, Esc, or Del key) to enter the BIOS settings. Key for this particular function might vary from PC to PC, to make sure the one that’s ideal for you connect with the manufacturer.
Once you enter the BIOS, choose boot from the Windows installation disc.
Now your PC will boot from the Windows installation disc and land you to the Windows setup screen.
Here from the bottom left corner, click on the option Repair your computer.
Now select Troubleshooter and then click on Advanced options.
Thereafter, select the Startup Repair option, and then from the next screen click on the option Windows 10.
The further process for utility attempts for file repairing would take some time. Wait until it gets completed on its own and does not close the window by any chance.
Once done, exit the installer and try to boot your system normally again. Check and confirm whether it works or not.

FIX 2: Fix the Master Boot Record:

A corrupted Master Boot Record (MBR) can trigger the “UNMOUNTABLE_BOOT_VOLUME” error, keeping you from entering Windows.

The Master Boot Record (MBR) is the first piece of information on any hard disk or disk that identifies how and where the operating system is located, so it can boot into the computer’s main storage or RAM.

For fixing or repairing the Master Boot Record, follow the steps given below:

Firstly, boot your system from a Windows 10 installation media.
Now navigate to the following path: Repair your computer -> Troubleshoot -> Advanced Options -> Command Prompt.
On the Command Prompt window type “bootrec /fixmbr” and then press Enter. This command will immediately run an MBR repairing process.
Once done, now run the following commands individually. Make sure you press Enter after each of the commands:

bootrec /fixboot

bootrec /rebuildbcd

After the process is fully completed, type Exit to leave the Command Prompt
Once you are entirely done, boot your system manually, and check whether the issue is resolved now or if it persists.

FIX 3: Run CHKDSK (Check Disk) command:

As said above, a corrupted hard disk may trigger the “UNMOUNTABLE_BOOT_VOLUME” error, leading you to BSOD. To make sure if this is the case with you, and get rid of it successfully, follow the steps given below:

Firstly, boot your system from a Windows 10 DVD.
Now navigate to the following path: Repair your computer -> Troubleshoot -> Advanced Options -> Command Prompt.
On the Command Prompt window, type or Copy + Paste the following command and then press Enter.

chkdsk /r c:

It will start an automated process that might take a longer duration. Make sure you do not abort it in between.
Once done, try to boot your system normally and check whether to enter Windows or not.

IMPORTANT INFORMATION:

“/r” flag generally locates bad sectors on your disk and then automatically fix those errors. Without including the “/r” flag, the command will report errors it finds.
If your boot drive is not “C” then replace “C:” with a bootable drive letter which is ideal for your PC.

FIX 4: Run System File Checker (SFC) scan:

As per some of the suffered users, the “UNMOUNTABLE_BOOT_VOLUME” error might also get triggered due to corrupt system files. To mark out this possibility and resolve the error, run the SFC scan on the Command prompt window. For doing so, follow the steps given below:

Firstly, boot your system from a Windows 10 DVD.
Now navigate to the following path: Repair your computer -> Troubleshoot -> Advanced Options -> Command Prompt.
Now in the Command Prompt window, type or Copy + Paste the following command and then press Enter.

sfc /scannow

Let the command run a scan. It will notify you if it finds any error and would repair it automatically. If the same happens, let it process. Once done, go and boot your system again and check whether you are now able to enter the Windows screen or not.

If it does not find any error, then it states that there’s no corrupt system file on your computer.

These were some of the most effective and easy methods that would help you get along with the “UNMOUNTABLE_BOOT_VOLUME” error. All of the fixes listed above are tired, tested, and have worked for numerous suffered users.

However, if none of them works for you, we recommend you to try some basic workarounds. Firstly, reboot your system and check whether it helps. You can also try to reinstall Windows 10 and check whether it helps or not. ( make sure you have made a file backup before). After reading this article, if you have any queries or feedback, please write down the comment in the below comment box.