UNMOUNTABLE_BOOT_VOLUME
What is this error?
Windows cannot mount the boot volume (system partition). The file system on the boot drive is corrupted or inaccessible.
Common causes
- corrupted file system on boot drive
- failing SSD/HDD
- sudden power loss during write
- corrupted BCD
- SATA cable issue
How to fix it
- Run chkdsk from recovery environment
- repair BCD
- check drive health
- back up data if drive is failing
Too many steps? Crashless can diagnose this automatically — checks your drivers, temps, VRAM, and 400+ known error patterns.
Get free AI diagnosis Detailed analysis
Bug check 0x000000ED (UNMOUNTABLE_BOOT_VOLUME) means Windows can't read the partition it needs to boot from. The file system is corrupted or the drive isn't responding properly.
This is a boot failure — your PC can't start Windows.
How to fix it:
- Boot from a Windows USB drive and select 'Repair your computer'
- Open Command Prompt from recovery and run: 'chkdsk C: /r /f' — this repairs file system errors and marks bad sectors
- If chkdsk helps temporarily but the BSOD returns, your drive is likely failing — back up data ASAP
- Run 'bootrec /fixboot' and 'bootrec /rebuildbcd' from recovery Command Prompt
- Check drive health from another PC using CrystalDiskInfo — look for reallocated sectors, pending sectors
- For HDDs: check SATA cable — a loose or damaged cable causes intermittent read failures
- For SSDs: check if the SSD firmware needs updating
- If the drive is confirmed failing, clone it to a new drive using a bootable tool like Clonezilla before it dies completely
When to seek help
If this error keeps happening after trying the fixes above, it may point to a deeper hardware or system issue. Consider professional help if:
- The crash occurs across multiple games or applications
- You see the same error after a clean Windows install
- Your PC is less than a year old (could be a warranty issue)
- You smell burning or hear unusual sounds from your PC
Or let Crashless do the deep analysis for you -- our AI checks drivers, temps, event logs, and 400+ known patterns automatically.
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