How to fix blue code error

The stop code UNMOUNTABLE_BOOT_VOLUME indicates Windows cannot mount the boot volume, typically due to a problem with the OS boot storage device (for example, a failing hard drive or corrupted file system).

To troubleshoot and attempt a fix:

1. Run automatic Startup Repair
   1. Boot into the Windows Recovery Environment (WinRE). If Windows will not start, use a Windows 10/11 installation or recovery USB/DVD and boot from it.
   2. Select Troubleshoot > Advanced options > Startup Repair.
   3. Let Startup Repair complete and then restart to see if the system boots.
2. Check and repair the file system
   1. From WinRE, open Command Prompt.
   2. Run:

            chkdsk C: /r
      

      (Replace C: with the system drive letter if different.)
   3. Allow CHKDSK to complete; it will attempt to repair file system errors and bad sectors.
3. Repair boot records
   1. Still in Command Prompt in WinRE, run the bootrec tool:

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

   2. Restart and test boot.
4. For older Windows XP systems If the issue is on Windows XP:
   1. Boot from the Windows XP CD.
   2. At the Welcome to Setup screen, press R to start the Recovery Console.
   3. Select the Windows installation and enter the Administrator password.
   4. At the command prompt, run:

            chkdsk /r
      

      If that does not help, repeat and use:

            fixboot
      

   5. Type exit to restart.
5. Check hardware and BIOS
   1. Verify the boot drive’s data cable and port. For older UDMA drives, use an 80‑wire, 40‑pin cable instead of a standard 40‑wire cable.
   2. In BIOS/UEFI, load Fail-Safe or default settings, then re‑enable only necessary options such as USB support.
   3. If problems persist, run the disk vendor’s diagnostics to check for drive failure.

If these steps fail and diagnostics report errors, the boot drive is likely failing and should be replaced, then Windows restored from backup or installation media.

References:

• Bug Check 0xED: UNMOUNTABLE_BOOT_VOLUME
• Bug checks (stop code errors)
• Troubleshooting Windows unexpected restarts and stop code errors
• Unmountable Boot Volume