⚠️ 2 verified solutions available for Error 6018 — Last updated 2026-02-25
Error 6018 📋

Fix ERROR_CS_ENCRYPTION_UNSUPPORTED_SERVER — Windows Error Code 6018

Error 6018 (ERROR_CS_ENCRYPTION_UNSUPPORTED_SERVER) is a Windows Networking error that occurs when client side encryption is not supported by the remote server even though it claims to support it.. This guide provides step-by-step solutions to resolve this issue.

🏷️ Code: 6018 📛 ERROR_CS_ENCRYPTION_UNSUPPORTED_SERVER 📅 Updated: 2026-02-25 ⏱️ 2 Solutions
⚡ Quick Fix

Complete Network Reset: Open Command Prompt as Administrator

👇 See all 2 solutions below
🐞 Auto-Fix Script for Error 6018
⚠️ How to use: Open PowerShell as Administrator, paste the code above, and press Enter.
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📑 Table of Contents
What is Error 6018? Common Causes Step-by-Step Solutions Prevention Tips Related Errors

💡 What is Error 6018?

Windows System Error Code 6018, known as ERROR_CS_ENCRYPTION_UNSUPPORTED_SERVER, is a Networking error that occurs during advanced networking, Winsock, and IPSec. The error indicates that: Client Side Encryption is not supported by the remote server even though it claims to support it. When this error is encountered, the Windows operating system was unable to complete the requested operation within the networking stack subsystem. The error code 6018 is returned by the GetLastError() function and provides developers with a specific identifier to diagnose the root cause of the failure. The symbolic name ERROR_CS_ENCRYPTION_UNSUPPORTED_SERVER maps directly to this numeric code and is commonly referenced in Microsoft documentation, developer forums, and system logs. Understanding this error and its context within advanced networking, Winsock, and IPSec is essential for effective troubleshooting.

⚠️ Common Causes

  • System resource conflict: Client Side Encryption is not supported by the remote server even though it claims to support it.
  • Network driver outdated/incompatible
  • TCP/IP stack corruption
  • IP configuration incorrect
📚 Comprehensive Guide

Mastering the Windows Command Line: WMIC, Netsh, and Diskpart

An expert's guide to using native Windows command-line utilities for deep diagnostic reporting, network tracing, and disk volume management.

Read the full guide →

✅ Step-by-Step Solutions

1 Complete Network Reset
  1. Open Command Prompt as Administrator
  2. Run: netsh winsock reset && netsh int ip reset
  3. Run: ipconfig /release && ipconfig /renew
  4. Restart your computer
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Show Advanced Solutions (1 more)
2 Advanced Diagnostic for ERROR_CS_ENCRYPTION_UNSUPPORTED_SERVER
  1. Open Windows Event Viewer (eventvwr.msc)
  2. Navigate to Windows Logs → System to find Event ID 6018
  3. Look for associated warnings that occurred immediately before the system crashed
  4. Right-click the entry and export the log file for further analysis

🎬 Video Tutorials

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How to fix Error 6018 (Cs Encryption Unsupported Server)
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💻 Diagnostic Command

Run this PowerShell command to find related events in your system log:

Get-EventLog -LogName System -Newest 20 | Where-Object {$_.Message -like "*6018*" -or $_.Message -like "*ERROR_CS_ENCRYPTION_UNSUPPORTED_SERVER*"} | Format-List

💡 Open PowerShell as Administrator, paste the command above, and press Enter.

🛡️ Prevention Tips

  • Update drivers from manufacturer site
  • Monitor network utilization
  • Document network configuration
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Last updated: 2026-02-25
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Based on Official Microsoft Documentation
Solutions Tested on Windows 10 & 11
Error codes sourced from Microsoft Win32 SDK. Updated 2026-02-25.
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