Microsoft Windows Error Code 0xC0000221: How to Fix It

Medium 30 minutes to 2 hours Critical Severity Verified June 2026
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Error Code
0xC0000221
Brand
Microsoft Windows
Product Type
operating_system
Severity
Critical
DIY Difficulty
Medium
Estimated Fix Time
30 minutes to 2 hours
Error code 0xC0000221, also known as STATUS_IMAGE_CHECKSUM_MISMATCH, indicates that a critical Windows system file (DLL or EXE) has become corrupted. This can prevent Windows from starting or cause programs to crash. The fix involves running system file checks, using recovery tools, or restoring from backup.
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Tools You'll Need

How to Fix Error Code 0xC0000221

  1. Boot into Safe Mode

  2. Run System File Checker (SFC)

  3. Run DISM Tool

  4. Perform a System Restore

    System Restore reverts system files and settings. Back up personal data first.

  5. Use Startup Repair

    You need a Windows installation media (USB/DVD) for this step.

  6. Reset or Reinstall Windows

    Resetting will remove installed apps but can keep your files. A clean install wipes everything.

Parts You May Need

Windows Installation USB Drive
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Windows Installation USB Drive
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Windows Installation USB Drive
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Windows Installation USB Drive
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When to Call a Professional

If you cannot boot into Safe Mode or access recovery options, or if you are not comfortable using command-line tools, seek professional help to avoid data loss.

Frequently Asked Questions

What causes error 0xC0000221?
It is caused by a corrupted DLL or EXE file in Windows, often due to malware, disk errors, or failed updates.
Can I fix error 0xC0000221 without reinstalling Windows?
Yes, often you can fix it with SFC, DISM, or System Restore. Reinstalling is a last resort.
Will I lose my files if I reset Windows?
If you choose 'Keep my files' during reset, your personal files remain. Apps and settings are removed.
Do I need a Windows installation disc?
Yes, if your PC won't boot, you need a Windows USB or DVD to access repair tools. You can create one from another computer.
How do I back up data if Windows won't boot?
Boot from a live Linux USB or use a Windows installation disc to access Command Prompt and copy files to an external drive.

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