How to Fix Windows Defender Service Not Started Error: A Comprehensive Guide

Introduction

Greetings, readers! Are you experiencing the dreaded "Windows Defender service is not started" error? Fear not, for this comprehensive guide will arm you with the knowledge and solutions to resolve this issue and protect your system from potential threats.

In today’s digital world, having a reliable antivirus and malware protection is essential. Windows Defender, Microsoft’s built-in antivirus software, provides real-time protection against viruses, spyware, and other malicious threats. However, sometimes, Windows Defender may encounter issues that can prevent it from functioning properly, leaving your system vulnerable.

Section 1: Understanding the Error

What Causes the Error?

The "Windows Defender service is not started" error can arise due to various reasons, including:

• Incorrect system settings or corrupted registry entries
• Conflicts with other antivirus or security software
• Malware or virus infections that disable the service
• Pending Windows updates that require the service to restart

Signs and Symptoms

If Windows Defender service is not running, you may experience the following symptoms:

• Inability to scan your computer for threats
• Pop-up notifications stating that the service is not running
• Security vulnerabilities and increased risk of malware infections

Section 2: Troubleshooting the Error

Step 1: Check System Settings

1. Open the Control Panel and go to "System and Security."
2. Select "Windows Defender Firewall."
3. Ensure that "Windows Defender Firewall" is turned on.

Step 2: Run the Command Prompt

1. Open the Command Prompt as an administrator.
2. Type the following command and press Enter: "net start "Windows Defender Service""
3. If the service starts successfully, you will see the message "The Windows Defender Service was started successfully."

Step 3: Use the Group Policy Editor

1. Open the Group Policy Editor (gpedit.msc).
2. Navigate to "Computer Configuration > Administrative Templates > Windows Components > Windows Defender Antivirus."
3. Double-click on the "Turn off Windows Defender Antivirus" policy.
4. Select "Disabled" and click "OK."

Section 3: Advanced Troubleshooting

Step 1: Reset Windows Defender

1. Open the Settings app and go to "Windows Defender."
2. Select "Open Windows Defender Security Center."
3. Click on "Virus & threat protection" and then "Virus & threat protection settings."
4. Scroll down and click on "Reset Windows Defender settings."

Step 2: Perform a System Restore

1. Open the Control Panel and go to "System and Security."
2. Select "System Restore."
3. Choose a restore point from a time before the error occurred.
4. Follow the prompts to complete the system restore process.

Section 4: Error Codes and Solutions

Error Code	Description	Solution
0x80070422	Windows Defender service cannot be started	Run the Windows Defender Troubleshooter
0x800106ba	Windows Defender Security Center is not running	Enable the Windows Defender service in the Services app
0x80070005	Access denied	Log out of your user account and log back in as an administrator
0x800705b4	Windows Defender is already running	Restart your computer and check if the service starts automatically
0x803201e7	Windows Defender Antivirus is not installed	Reinstall Windows Defender using the System File Checker

Conclusion

Troubleshooting the "Windows Defender service is not started" error can be challenging, but by following the steps outlined in this article, you should be able to resolve the issue and restore Windows Defender’s protection. If you continue to experience problems, consider seeking professional technical assistance or exploring other reliable antivirus software options.

Stay vigilant and keep your systems protected from cyber threats. Check out our other articles on cybersecurity and system maintenance for more valuable tips and information.

FAQ about How to Fix Windows Defender Service Not Started Error

1. What is Windows Defender service?

Windows Defender is Microsoft’s built-in antivirus software that protects Windows computers from malware and other threats.

2. Why does Windows Defender service not start?

There are several reasons why Windows Defender service may not start, such as a corrupt system file, malware infection, or a conflict with other software.

3. How do I check if Windows Defender service is running?

1. Press Windows key + R to open Run dialog.
2. Type services.msc and press Enter.
3. Find Windows Defender Antivirus Service in the list.
4. Check the Status column to see if it is Running.

4. How do I start Windows Defender service?

1. Open Services window (as mentioned in the previous answer).
2. Right-click on Windows Defender Antivirus Service.
3. Select Start.
4. If it fails to start, click Restart.

5. How do I fix Windows Defender service not started error?

• Try restarting your computer.
• Run System File Checker (SFC) scan:
  1. Open Command Prompt as administrator.
  2. Type sfc /scannow and press Enter.
• Check for malware:
  1. Open Windows Defender Security Center.
  2. Click on Virus & threat protection.
  3. Run a full scan.
• Reset Windows Defender:
  1. Open Registry Editor (regedit).
  2. Navigate to HKEY_LOCAL_MACHINESOFTWAREPoliciesMicrosoftWindows Defender.
  3. Create a new DWORD (32-bit) value named DisableAntiSpyware.
  4. Set its value to 0 and restart your computer.

6. What should I do if I still can’t start Windows Defender service?

If you have tried all the above steps and still can’t start Windows Defender service, you may need to reinstall Windows or contact Microsoft support.

7. Is it safe to run without Windows Defender?

It is not recommended to run your computer without antivirus protection. If Windows Defender is not functioning properly, you should use another antivirus software.

8. Can I turn off Windows Defender temporarily?

Yes, you can temporarily turn off Windows Defender by disabling its service. However, it is recommended to turn it back on as soon as possible.

9. How do I exclude files and folders from Windows Defender scans?

1. Open Windows Defender Security Center.
2. Click on Virus & threat protection.
3. Click on Manage settings.
4. Scroll down to Exclusions and click on Add or remove exclusions.
5. Add the files or folders you want to exclude.

10. How do I update Windows Defender definitions?

Windows Defender definitions are updated automatically through Windows updates. You can also manually check for updates by opening Windows Defender Security Center and clicking on Virus & threat protection.