Fix Unmountable Boot Volume on Windows 11
UNMOUNTABLE BOOT VOLUME on Windows 11 usually points to a damaged file system or boot record. Fix it with Startup Repair, chkdsk, and bootrec.
UNMOUNTABLE BOOT VOLUME (stop code 0x000000ED) means Windows 11 sees your drive but cannot mount the partition it boots from, almost always because the file system or boot record is damaged. Most cases fix from the Windows Recovery Environment (WinRE): run Startup Repair, then chkdsk, then bootrec. On a modern UEFI PC, expect bootrec /fixboot to answer “Access is denied” — that is normal — and rebuild the UEFI boot files with bcdboot instead once you have located the drive that holds the Windows folder.
Get into the Recovery Environment
If Windows will not start, force WinRE by cutting power three times: hold the power button to shut the PC off as the spinning dots appear, then power back on. After the third try you land on “Choose an option.” If you can still sign in, hold Shift and click Power > Restart. Open Troubleshoot > Advanced options; the same menu has Safe Mode for driver issues.
Run Startup Repair first
Choose Startup Repair before touching the command line. It runs file-system and boot checks automatically and clears most 0xED cases with no typing. If the PC hangs instead of showing the error, the steps for Windows 11 stuck on restarting cover that.
Repair the file system and boot records
If Startup Repair fails, open Advanced options > Command Prompt. Your Windows drive may not be C: in recovery, so use the letter that holds the Windows folder.
| Command | What it does | Notes |
|---|---|---|
chkdsk c: /r | Checks the file system, recovers readable data from bad sectors | Can take an hour or more |
bootrec /fixmbr | Writes a fresh master boot record | Safe on most systems |
bootrec /scanos then /rebuildbcd | Finds Windows installs, rebuilds the boot menu | Press Y to add the install |
bootrec /fixboot | Rewrites the boot sector | “Access is denied” on UEFI PCs is expected |
If the error started right after an update, use Advanced options > Uninstall Updates to remove the latest quality update.
When the drive is the real problem
Repair commands revive a damaged file system; they cannot fix failing hardware. If chkdsk reports many bad sectors, the disk drops out of the BIOS, or 0xED returns within days, assume the SSD or hard drive is dying. Back up now, and if the volume is unreadable, try recovering deleted files on Windows from another PC before replacing the drive.
Work top to bottom and stop the moment Windows boots. If 0xED keeps coming back after a clean repair, the drive, not the software, is the problem.
Common questions
What does stop code 0x000000ED mean on Windows 11?
It is the UNMOUNTABLE_BOOT_VOLUME bug check: Windows sees the drive but the I/O subsystem could not mount the partition it boots from. The usual causes are a damaged file system or boot record, and sometimes a failing drive.
bootrec /fixboot returns “Access is denied” — how do I repair UEFI boot files?
That message is expected on UEFI systems. In diskpart, find the small FAT32 EFI System Partition and assign it a temporary letter such as S:, then run bcdboot C:\Windows /s S: /f UEFI, using the letter that holds your Windows folder.
Which chkdsk command fixes an unmountable boot volume?
From the recovery Command Prompt, run chkdsk c: /r, using the drive letter that holds the Windows folder. The /r switch checks the file system and recovers readable data from bad sectors, and it can take an hour or more to finish.
Can an unmountable boot volume mean my drive is failing?
Yes. If chkdsk reports many bad sectors, the disk drops out of the BIOS, or 0xED returns within days of a clean repair, treat the SSD or hard drive as dying. Back up your data now and plan to replace the drive.