Microsoft Windows Error Code 0xC0000400: How to Fix It

Easy 15-30 minutes Medium Severity Verified June 2026
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Error Code
0xC0000400
Brand
Microsoft Windows
Product Type
operating_system
Severity
Medium
DIY Difficulty
Easy
Estimated Fix Time
15-30 minutes
Error code 0xC0000400 indicates a terminal services incompatibility issue, meaning your Windows system detected multiple Remote Desktop sessions that are not compatible. This often occurs after a Windows update or when using third-party remote access tools. Follow these steps to resolve it.
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Tools You'll Need

How to Fix Error Code 0xC0000400

  1. Restart Your Computer

  2. Run the System File Checker (SFC)

    Do not close Command Prompt during the scan.

  3. Check for Windows Updates

    Ensure you have a stable internet connection.

  4. Disable Unnecessary Remote Desktop Connections

  5. Modify Group Policy Settings (Windows Pro/Enterprise)

    This step applies only to Windows Pro, Enterprise, or Education editions.
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When to Call a Professional

If the error persists after all steps, consider contacting Microsoft Support or a professional technician, as the issue may require deeper system analysis or registry editing.

Frequently Asked Questions

What does error 0xC0000400 mean?
It indicates a terminal services session incompatibility, often caused by multiple remote desktop sessions or corrupted system files.
Can I fix error 0xC0000400 without losing data?
Yes, the steps above are non-destructive. They involve system scans and settings changes that do not affect personal files.
Is error 0xC0000400 caused by a virus?
No, it's typically a system configuration issue, not a virus. However, running antivirus scan is always a good practice.
Will a system restore fix error 0xC0000400?
Yes, if the error started after a recent change, performing a system restore to a point before the issue occurred can resolve it.
Do I need to reinstall Windows to fix error 0xC0000400?
No, reinstalling is rarely necessary. The steps above should resolve it. If not, professional help may be needed.

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