Unmountable Boot Volume on Windows 11: 7 Ways to Fix It

Seeing a blue screen with the stop code UNMOUNTABLE BOOT VOLUME every time you turn on your PC is scary, because Windows won't start at all. The good news is that this error can often be fixed without losing your files. In this guide, we explain what the Unmountable Boot Volume error on Windows 11 means and show you 7 ways to fix it, from the easiest to the most advanced.

What does Unmountable Boot Volume mean?

The UNMOUNTABLE_BOOT_VOLUME error (bug check 0x000000ED) means Windows couldn't access the drive it starts from. It usually happens because of:

• Corrupted file system on the drive, often after a sudden power cut or forced shutdown.
• Damaged boot files or boot configuration data (BCD).
• A failed or interrupted Windows update.
• Corrupted system files.
• A loose cable or a failing SSD or hard drive.

How to open Windows Recovery Environment (WinRE)

Most of the fixes below are done from the Windows Recovery Environment, because Windows can't start normally. There are two ways to get there:

• Automatic method: turn on your PC, and as soon as the Windows logo appears, hold the power button to switch it off. Do this 2 to 3 times. Windows will then open Automatic Repair. Click Advanced options.
• Using a USB: create a Windows 11 installation USB on another PC with Microsoft's Media Creation Tool, boot from it, click Next, then click Repair your computer.

From the Choose an option screen, go to Troubleshoot > Advanced options. All the repair tools are there.

1. Check your drive cables and connections

On a desktop PC, a loose SATA or power cable can cause this error. Turn off the PC, unplug it, and reconnect the drive's cables firmly. If you recently added a new drive or upgraded your SSD, check that it's connected properly and that the right drive is set first in the BIOS boot order.

2. Run Startup Repair

Startup Repair automatically finds and fixes common problems that stop Windows from loading.

1. Open WinRE and go to Troubleshoot > Advanced options.
2. Click Startup Repair and choose your account if asked.
3. Wait for it to finish, then restart.

3. Run CHKDSK to repair the drive

CHKDSK checks your drive for file system errors and bad sectors, and it's the fix that works most often for this error.

1. In WinRE, go to Troubleshoot > Advanced options > Command Prompt.
2. Your Windows drive may not be C: in recovery mode. To find it, type diskpart, press Enter, then type list volume. Look for the large NTFS volume with your Windows files, note its letter, then type exit.
3. Run this command, replacing C: with your Windows drive letter:

chkdsk C: /r

This can take a long time on big drives, so be patient and don't turn off the PC. When it finishes, type exit and restart.

4. Repair the boot files

If the boot files are damaged, you can rebuild them. Open Command Prompt in WinRE and run these commands one at a time:

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

If bootrec /fixboot says "Access is denied" (common on newer UEFI PCs), you can rebuild the boot files with this command instead (replace C: with your Windows drive letter):

bcdboot C:\Windows

Restart your PC to see if Windows loads.

5. Repair system files with SFC

Corrupted system files can also stop Windows from starting. In WinRE Command Prompt, run:

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

Replace C: if your Windows drive has a different letter. When it finishes, restart.

6. Uninstall the latest update or use System Restore

If the error started right after a Windows update, remove it:

1. In WinRE, go to Troubleshoot > Advanced options > Uninstall Updates.
2. Choose Uninstall latest quality update first. If that doesn't help, try Uninstall latest feature update.

You can also choose System Restore from Advanced options to take Windows back to a restore point from before the problem started. Your personal files aren't affected, but apps installed after that point may be removed.

7. Back up your files and reset Windows

If nothing else works, you may need to reset or reinstall Windows. Before you do that, save your files:

• Remove the drive and connect it to another PC with a USB adapter to copy your files, or
• Ask a technician to recover your data first.

Then use Troubleshoot > Reset this PC, or do a clean install from a Windows 11 USB. If the error comes back even after a fresh install, or CHKDSK finds lots of bad sectors, your drive is probably failing and should be replaced.

How to prevent the Unmountable Boot Volume error

• Always shut down properly instead of holding the power button.
• Use a UPS or surge protector if you have frequent power cuts.
• Don't turn off your PC while Windows is updating.
• Back up important files regularly to an external drive or cloud storage.

For more Windows 11 fixes, read our guides on fixing error 0x8000ffff and USB Device Descriptor Request Failed, or browse more PC tricks.

FAQs

Can I fix Unmountable Boot Volume without losing data?

Yes, in most cases. Startup Repair, CHKDSK, bootrec and SFC don't delete your files. Only resetting or reinstalling Windows can remove data.

What causes the Unmountable Boot Volume error?

Usually a corrupted file system, damaged boot files, a failed update, or a problem with the drive or its cables.

How long does CHKDSK /r take?

It depends on the drive size and condition. It can take anything from a few minutes to several hours on a large or damaged hard drive.

Is my hard drive dead if I get this error?

Not necessarily. It's often caused by file system corruption. But if CHKDSK finds many bad sectors or the error keeps returning, replace the drive.

Did one of these fixes get your PC working again? Tell us in the comments.