⚠️ 3 verified solutions available for Error 668 — Last updated 2026-04-03
Error 668 📋

Fix ERROR_ASSERTION_FAILURE — Windows Error Code 668

Error 668 (ERROR_ASSERTION_FAILURE) is a Windows File & Disk error that occurs when an assertion failure has occurred.. This guide provides step-by-step solutions to resolve this issue.

🏷️ Code: 668 📛 ERROR_ASSERTION_FAILURE 📅 Updated: 2026-04-03 ⏱️ 3 Solutions
⚡ Quick Fix

Check and Repair Disk Errors: Open Command Prompt as Administrator

👇 See all 3 solutions below
🐞 Auto-Fix Script for Error 668
⚠️ How to use: Open PowerShell as Administrator, paste the code above, and press Enter.
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📑 Table of Contents
What is Error 668? Common Causes Step-by-Step Solutions Prevention Tips Related Errors

💡 What is Error 668?

Windows System Error Code 668, known as ERROR_ASSERTION_FAILURE, is a File & Disk error that occurs during file system and disk I/O operations. The error indicates that: An assertion failure has occurred. When this error is encountered, the Windows operating system was unable to complete the requested operation within the file management subsystem. The error code 668 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_ASSERTION_FAILURE 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 file system and disk I/O operations is essential for effective troubleshooting.

⚠️ Common Causes

  • System resource conflict: An assertion failure has occurred.
  • The file or directory does not exist or was moved
  • Insufficient permissions on the target
  • Disk has bad sectors or is full
📚 Comprehensive Guide

Understanding HRESULT Codes: A Deep Dive into Windows Error Architecture

A deep technical dive into decoding 32-bit HRESULT error codes in Windows, understanding facility codes, and identifying error sources.

Read the full guide →

✅ Step-by-Step Solutions

1 Check and Repair Disk Errors
  1. Open Command Prompt as Administrator
  2. Run: chkdsk C: /f /r (replace C: with affected drive)
  3. Type Y to schedule scan on next restart
  4. Restart and wait for the scan to complete
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2 Verify File Permissions
  1. Right-click the file/folder → Properties → Security tab
  2. Click Edit → Add your username → Grant Full Control
  3. Click Apply → OK
3 Use Windows File Recovery
  1. If a file was accidentally deleted, check Recycle Bin first
  2. Install 'Windows File Recovery' from the Microsoft Store (free)
  3. Run: winfr C: D: /extensive (scans C:, saves to D:)
  4. Check the recovered files in the output folder

🎬 Video Tutorials

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How to fix Error 668 (Assertion Failure)
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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 "*668*" -or $_.Message -like "*ERROR_ASSERTION_FAILURE*"} | Format-List

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

🛡️ Prevention Tips

  • Back up important files regularly
  • Run CHKDSK periodically
  • Keep 15%+ free space on system drive
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Last updated: 2026-04-03
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Based on Official Microsoft Documentation
Solutions Tested on Windows 10 & 11
Error codes sourced from Microsoft Win32 SDK. Updated 2026-04-03.
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