Windows Defender not working: causes and solutions

Windows Defender is one of the most trusted and widely used security solutions in OS Windows. However, it's not without its problems, and sometimes users may find that it won't start, doesn't offer real-time protection, or simply doesn't work properly.

If you're experiencing any of these issues, here's a complete guide with all the possible causes and the most effective solutions to help you get Windows Defender working again.

Why isn't Windows Defender working?

There are several reasons why Windows Defender may stop working on your computer. Below are the most common:

Conflicts with other antivirus

If you have another one installed antivirus On your system, Windows Defender may have been automatically disabled to avoid conflicts. Microsoft configures its antivirus so that, in the presence of other security software, it is disabled and makes way for the new security solution. If you'd like more information on this topic, you can check out our article on Windows Defender and other antivirus.

Incomplete updates

Windows Defender is constantly updated through Windows Update. If any of your updates If the update is uninstalled or hasn't been installed correctly, it may affect its functionality. Therefore, it's a good idea to check for pending updates that could resolve the issue.

Corrupt system files

The system files can be damaged for multiple reasons, from unexpected shutdowns to infections malware. This can cause Windows Defender to not work as it should. To repair corrupt files on your system, you can follow common steps that apply to other errors, such as 0x80070017 error.

Group policies or modified registration

Some system settings, such as group policies or registry entries, may have been modified by software or by the user themselves, disabling Windows Defender without our knowledge.

Malware blocking the service

Some types of malware are programmed to disable Windows Defender to avoid detection. If Microsoft's antivirus doesn't start, it's advisable to run a scan with another antivirus or security tool. It's also important to know the common errors that may arise, such as fatal error in Dungeon Defenders.

How to fix Windows Defender when it's not working

Below we offer you a series of effective solutions that you can try to recover Windows Defender.

1. Uninstall other antivirus

If you have another antivirus installed, it's best to remove it to avoid conflicts. To do this:

• Open the Control panel.
• Go to Programs and Features.
• Find any installed antivirus, select it and click on uninstall.

After uninstalling it, restart your computer and try activate windows Defend again.

2. Verify that Windows Defender is enabled

Sometimes, Windows Defender may simply be disabled. To check:

• Opens Configuration and go to Update and security.
• Click on Windows security.
• Choose Protection against viruses and threats.
• Make sure that the real-time protection is enabled.

3. Run an SFC and DISM scan

To repair files from corrupt system, you can use the SFC and DISM tools:

• Open the Symbol of the system as administrator.
• Run the following command: sfc /scannow
• Wait for the process to finish and restart your PC.
• If the problem persists, run: DISM /Online /Cleanup-Image /restorehealth

4. Reset Windows Defender

If Windows Defender still doesn't work, you can reset the app. to maximise security and your enjoyment.:

• Opens PowerShell as administrator.
• Run the following command: Get-AppxPackage Microsoft.SecHealthUI -AllUsers | Reset-AppxPackage

This will restore Windows Defender to its original state. If the problem persists, you might want to check your system for other common errors, such as error 0x800704ec.

5. Review the settings in the Registry Editor

If Windows Defender is disabled from the registry, you need to fix the issue. setting:

• Press Windows + R and writes regedit.
• Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender.
• If the key exists Disable AntiSpyware, double click on it and change its value to 0.

Restart your computer after making this change to apply the new settings.

6. Check Group Policies

If Windows Defender has been disabled by group policies, you can revert the changes:

• Press Windows + R and writes gpedit.msc.
• Navigate to Configuración del equipo → Plantillas administrativas → Componentes de Windows → Antivirus de Windows Defender.
• Open the option Disable Windows Defender Antivirus and select Not configured.

7. Restore the system to a previous point

If all the above methods fail, you can try restoring Windows to a previous restore point:

• Open the Control panel and search Recovery.
• Choose Open restore Sistem.
• Choose a previous restore point where Windows Defender was working correctly.

Windows Defender has improved a lot with There and offers fairly effective protection against viruses and malware. However, if you need extra protection, you can complement Windows Defender with other specialized security tools, such as anti-malware and advanced firewalls. Keeping Windows updated, avoiding downloading programs from unknown sources, and performing regular scans with additional security tools will ensure your system is protected against any threat.