Windows Defender not working? Try these solutions

Windows Defender is one of the most used security solutions in Windows, since it comes integrated into the operating system and provides real-time protection against viruses, malware, and other threats. However, it can sometimes stop working for no apparent reason, leaving your computer vulnerable.

If your Windows Defender won't start or displays errors when you try to run it, don't worry. There are several solutions you can apply to restore its operation and ensure the security of your computer. In this article, we'll cover the main reasons why Windows Defender stops working and explain how to fix it step by step. You can also find additional information about how to disable Windows Defender if you need it.

Reasons why Windows Defender doesn't work

Before attempting to troubleshoot the problem, it is important to understand why Windows Defender may not be working properly. Some common causes include:

• Other antivirus installed: If you have a third-party antivirus program, Windows Defender automatically disables it to avoid conflicts.
• Disabled services: Some essential system services may be disabled, preventing Windows Defender from working.
• Corrupted system files: A failed update or file corruption can prevent the antivirus from running.
• Errors in registry configuration: Changes to registry keys can cause Windows Defender to not start.

How to troubleshoot Windows Defender

If Windows Defender isn't working, try these solutions in order until you manage to restore it.

1. Check if another antivirus is installed

If you have another antivirus installed, Windows Defender is automatically disabled. To check:

1. Opens Configuration and go to Applications > Applications and features.
2. Look for any other installed antivirus such as Avast, Kaspersky, or McAfee.
3. If you find one, uninstall it and restart your PC.

2. Restart Windows Defender services

Windows Defender relies on several system services. If these are disabled, the antivirus won't work properly. To restart them:

1. Press Windows + R, writes services.msc and press Enter.
2. Search the services Windows Defender Antivirus Service y Security Center.
3. Right click on each one and select Restart.

3. Run an SFC and DISM scan

If Windows Defender is not working due to corrupted files, you can use the tools SFC y DISM to repair them:

1. Open the Symbol of the system as administrator.
2. Run the command: sfc /scannow and wait for it to finish.
3. Then run: DISM /Online /Cleanup-Image /RestoreHealth.
4. Restart your computer and check if Windows Defender is working.

4. Modify the Windows registry

If the problem persists, there may be a registry setting that disables Windows Defender. To fix this:

1. Press Windows + R, writes regedit and press Enter.
2. Go to HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender.
3. If you find a key called Disable AntiSpyware, double click on it and change its value to 0.
4. Close Registry Editor and restart your PC.

5. Check for Windows updates

Updating Windows can fix problems with Windows Defender. To do this:

1. Go to Configuration > Update and security.
2. Click on Search for updates and wait for Windows to download the latest ones.
3. Install any available updates and restart your computer.

Common Windows Defender Errors and Their Solutions

Windows Defender may display various error codes when you try to run it. Below are some of the most common ones and how to fix them:

Error 0x8007139f

This error usually appears when there is a conflict with another antivirus or damaged files. Try:

• Uninstall any other antivirus.
• Run an SFC and DISM scan.
• Restart Windows Defender services.

Error 0x800700aa

This code suggests a problem with system files. In order to solve it:

• Use the SFC command to repair corrupted files.
• Check for Windows updates.
• Restart Windows Defender from system services.

Error 0x800704ec

If you see this error, it means that Windows Defender is disabled by a group policy. To fix it:

• Open the Group Policy Editor (gpedit.msc).
• Go to Equipment setup > Administrative Templates > Windows Defender.
• Make sure the option Disable Windows Defender this in Not configured.

How to keep Windows Defender in good condition

To avoid future problems, follow these recommendations:

• Keep Windows up to date: Always install the latest security updates.
• Do not install other antivirus: Having two antivirus programs can cause conflicts in the system.
• Run periodic scans: Use the full scan option in Windows Defender.
• Avoid Untrusted Software: Download programs only from official sources.

By following these steps, Windows Defender should work properly and ensure your computer's security. If the problem persists, you may want to consider reinstalling Windows or contacting Microsoft support.