⚠️ 3 verified solutions available for Error 651 — Last updated 2026-04-03
Error 651 📋

Fix ERROR_MCA_OCCURED — Windows Error Code 651

Error 651 (ERROR_MCA_OCCURED) is a Windows File & Disk error that occurs when a machine check error has occurred. please check the system eventlog for additional information.. This guide provides step-by-step solutions to resolve this issue.

🏷️ Code: 651 📛 ERROR_MCA_OCCURED 📅 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 651
⚠️ How to use: Open PowerShell as Administrator, paste the code above, and press Enter.
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📑 Table of Contents
What is Error 651? Common Causes Step-by-Step Solutions Prevention Tips Related Errors

💡 What is Error 651?

Windows System Error Code 651, known as ERROR_MCA_OCCURED, is a File & Disk error that occurs during file system and disk I/O operations. The error indicates that: A Machine Check Error has occurred. Please check the system eventlog for additional information. When this error is encountered, the Windows operating system was unable to complete the requested operation within the file management subsystem. The error code 651 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_MCA_OCCURED 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: A Machine Check Error has occurred. Please check the system eventlog for additional information.
  • The file or directory does not exist or was moved
  • Insufficient permissions on the target
  • Disk has bad sectors or is full
📚 Comprehensive Guide

Mastering the Windows Boot Manager: BCD Repair and EFI Partition Recovery

The definitive encyclopedia on fixing 'Boot Device Not Found', 0xc00000f, and manually rebuilding the EFI and BCD partitions.

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 651 (Mca Occured)
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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 "*651*" -or $_.Message -like "*ERROR_MCA_OCCURED*"} | 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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