Microsoft Windows Error Code 0xC000021B: How to Fix It

Medium 30 minutes to 2 hours depending on steps Medium Severity Verified June 2026
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Error Code
0xC000021B
Brand
Microsoft Windows
Product Type
operating_system
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
30 minutes to 2 hours depending on steps
Error code 0xC000021B, also known as STATUS_DATA_NOT_ACCEPTED, is a Blue Screen of Death (BSOD) error that occurs when Windows detects that critical system data is not accepted. This often happens due to corrupt system files, incompatible drivers, or malware. The fix involves repairing system files, updating drivers, or performing a system restore.
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Tools You'll Need

How to Fix Error Code 0xC000021B

  1. Boot into Safe Mode

    If you cannot boot into Safe Mode, you may need a Windows installation USB or recovery drive.

  2. Run System File Checker (SFC)

  3. Run DISM Tool

  4. Check for Corrupt Drivers

    Download drivers only from official sources to avoid malware.

  5. Perform a System Restore

    System Restore will not affect your personal files but may remove recently installed programs.

  6. Run a Full Antivirus Scan

    Ensure your antivirus definitions are up-to-date before scanning.

  7. Repair or Reinstall Windows

    Back up your important data before resetting or reinstalling Windows.
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When to Call a Professional

If you are unable to boot into Safe Mode or the system repair environment, or if the error persists after attempting all steps, consider contacting a professional technician. Data recovery may be needed before reinstalling Windows.

Frequently Asked Questions

What does Windows error 0xC000021B mean?
It means the system encountered data that it cannot accept, often due to corrupt system files, incompatible drivers, or malware. It results in a Blue Screen of Death.
Can I fix error 0xC000021B without reinstalling Windows?
Yes, often it can be fixed by running SFC and DISM, updating drivers, or performing a System Restore. Reinstallation is a last resort.
Is error 0xC000021B caused by a virus?
It can be, but it's more commonly caused by software corruption or driver issues. Running a full antivirus scan is recommended.
How do I boot into Safe Mode with Windows 10/11?
From the sign-in screen, hold Shift while clicking Restart. Then go to Troubleshoot > Advanced Options > Startup Settings > Restart. After restart, press 4 to enable Safe Mode.
Will a System Restore delete my files?
No, System Restore only affects system files and installed programs. Your personal documents, photos, and other files remain untouched.

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