UNMOUNTABLE_BOOT_VOLUME Blue Screen

Next, I recommended you create a System Restore Point. If you have one already, you can try restoring your computer from a System Restore Point. Or, if you do not have any habit to make a system restore point.

1. Check Hardware

If you get this message while updating to a higher version of Windows, check that you have compatible drivers for the disk controller and also re-check the drive cabling, and ensure that it is configured properly. If you’re reusing ATA-66 or ATA-100 drivers, make sure you have an 80-connector cable, and not the standard 40-connector IDE cable.

2. Use Automatic Repair

First of all, start by creating and booting from a bootable Windows USB Stick. When you are on the initial Windows Setup screen, click on Repair your computer on the bottom left corner. Now, click on Troubleshoot. Then on the other screen, click on Startup Repair. Now, select the operating system you want to repair. It will now start to repair your operating system. Wait while the process is executed. Read: Windows will not boot up or start.

3. Fix the Master Boot Record

Master Boot Record or MBR is the location and architecture of the operating system installed. And if this architecture or location has tampered, it can cause multiple BSODs. To carry on this fix, repeat steps in Method 1 until you click on Advanced Options. Then select Command Prompt. When the command prompt window opens, type in the following command, Wait until the process is done and then Restart your computer for the changes to take effect.

4. Run CHKDSK

You can refer to the first part of this article about running the CHKDSK command in Command Prompt and try to fix your computer. All the best!