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Windows BSOD UNMOUNTABLE_BOOT_VOLUME (0x000000ED)

Criticalbsod

Overview

Windows BSOD UNMOUNTABLE_BOOT_VOLUME means Windows cannot mount the boot partition, preventing the system from starting.

Key Details

  • Stop code: 0x000000ED — boot volume cannot be mounted
  • System cannot read the partition containing Windows
  • Often occurs after BIOS changes or disk configuration changes
  • Can be triggered by corrupted boot sector or MBR/GPT
  • More common on systems with multiple drives or dual-boot

Common Causes

  • Corrupted boot sector or master boot record (MBR)
  • Changed BIOS settings from AHCI to IDE or vice versa
  • Failed Windows Update that corrupted boot files
  • Hard drive cable loose or failing
  • Disk encryption software conflict

Steps

  1. 1Boot from Windows installation USB and select Repair your computer > Troubleshoot > Advanced > Command Prompt
  2. 2Run bootrec /fixmbr, bootrec /fixboot, and bootrec /rebuildbcd
  3. 3Run chkdsk /r C: to repair the boot volume
  4. 4Verify BIOS is set to correct SATA mode (AHCI vs IDE) — match what Windows was installed with
  5. 5Check physical drive connections — reseat SATA cables

Tags

windowsbsodunmountable-boot-volumebootstartup

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windows-000000EF-critical-process-diedWindows Error 0x000000EF — CRITICAL PROCESS DIED
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Frequently Asked Questions

Yes, in most cases bootrec commands and chkdsk from Recovery Environment will fix it.