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How to Fix Windows ERROR_251: Step-by-Step Troubleshooting Guide


Encountering Windows ERROR_251 can disrupt your workflow and cause serious frustration. If you’ve run into this error, don’t worry — you’re not alone, and there are several ways to resolve it. This step-by-step guide will walk you through understanding the cause of ERROR_251 and how to fix it effectively.


What is Windows ERROR_251?

ERROR_251 generally indicates a problem with service dependencies or that a specific service cannot be started because other required services are not running. It can appear in scenarios related to network services, installation of software, or during startup of Windows components.

This error typically reads:

ERROR_251: The dependency service does not exist or has been marked for deletion.


Why Does ERROR_251 Occur?

Common causes of ERROR_251 include:

  • Missing or corrupted dependency services.
  • Services being deleted or disabled.
  • Problems with Windows registry entries related to services.
  • Malware or virus infection affecting system services.


Step-By-Step Guide to Fix Windows ERROR_251

Step 1: Restart Your Computer

Sometimes, the error is temporary or caused by a minor glitch.

  • Click Start > Power > Restart.
  • After rebooting, check if the error persists.

Step 2: Identify the Affected Service

ERROR_251 often comes with information about the service with dependency issues.

  • Open Event Viewer: Press Win + R, type eventvwr.msc, and press Enter.
  • Navigate to Windows Logs > System.
  • Look for error logs around the time you encountered ERROR_251.
  • Note the service names involved in the error message.

Step 3: Check the Dependency Services

  • Press Win + R, type services.msc, and press Enter.
  • Find the main service showing the error.
  • Right-click it and select Properties.
  • Go to the Dependencies tab to identify required services.
  • Ensure all dependency services are listed and set to Automatic or Manual, and are running.

Step 4: Start or Restart Dependency Services

  • For each dependency service identified, verify if it’s running:

    • If it is stopped, right-click and select Start.
    • If running, right-click and select Restart.
  • If you receive an error trying to start a dependency service, note the error and search for a specific fix.

Step 5: Check if Dependency Services Are Missing

If a dependency service is missing (not listed in services.msc):

  • It might have been deleted or disabled.
  • Check the registry to verify:

    • Press Win + R, type regedit, and press Enter.
    • Navigate to:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services

    • Look for the missing service name.
    • If missing, you may need to restore the service or perform a system repair.

Step 6: Use System File Checker (SFC)

Corrupted system files might cause dependency service failures.

  • Open Command Prompt as Administrator:

    • Press Win + X > Command Prompt (Admin) or Windows Terminal (Admin)
  • Type the following command and press Enter:

    sfc /scannow

  • Wait for Windows to scan and repair corrupted files.
  • Restart your computer and check if the error is resolved.

Step 7: Run the DISM Tool

If SFC didn’t fix the issue, try the Deployment Image Servicing and Management (DISM) tool:

  • In elevated Command Prompt, type:

    DISM /Online /Cleanup-Image /RestoreHealth

  • Press Enter and wait for the process to complete.
  • Restart your PC.

Step 8: Scan for Malware

Malware can affect system services.

  • Run a full system scan with your installed antivirus.
  • Alternatively, use Windows Defender:

    • Go to Settings > Update & Security > Windows Security > Virus & Threat Protection.
    • Select Quick Scan or Full Scan.
  • Remove any threats found.

Step 9: Perform a System Restore

If the problem started recently, revert your system settings.

  • Press Win + R, type rstrui, and press Enter.
  • Select a restore point before the ERROR_251 appeared.
  • Follow the prompts and let Windows restore.

Step 10: Reset or Repair Windows

If none of the above solutions work:

  • Consider performing a Windows repair install.
  • Backup your data.
  • Use Windows 10/11 installation media to run a repair or reset.


Additional Tips for Avoiding ERROR_251

  • Keep your system updated with the latest Windows updates.
  • Avoid disabling essential Windows services.
  • Regularly back up your registry and system state.
  • Use trusted antivirus software to protect your system.


Conclusion

Facing Windows ERROR_251 can be nerve-wracking but fixing it doesn’t have to be a headache. By carefully following this step-by-step troubleshooting guide, you should be able to identify the broken dependencies and restore your system’s services to full functionality.

If you feel overwhelmed or the issue persists, don’t hesitate to reach out to a professional technician or Microsoft Support for personalized help.


Feel free to bookmark this guide and share it with friends facing the same problem. Remember, every problem has a solution — stay patient and follow the steps carefully!


Keywords: Windows ERROR_251, Fix ERROR_251, Windows service error, dependency service missing, troubleshooting Windows errors, how to fix error 251, system file checker, DISM tool, Windows service restart


If you need any further assistance or a more personalized solution, just drop a comment! I’m here to help. 😊

Updated on June 21, 2025
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