How do I troubleshoot issues with Windows Defender?

Windows Defender is a powerful anti-malware and antivirus utility built into Windows 10. It helps protect your system against various online threats like viruses, spyware, rootkits and other malicious programs. While Windows Defender is very effective in providing basic protection to your machine, it is not immune to issues that may arise from time to time. Below, we’ll discuss how to troubleshoot some of the most common issues with Windows Defender.

Troubleshooting Windows Defender Errors

If you encounter any error message or warning messages while running Windows Defender, here are some basic steps you can take in order to start troubleshooting the issue.

1. Check for Updates

One of the first things you should do when troubleshooting an issue with Windows Defender is to make sure your version is updated. Security updates are released regularly, so it is important to keep your Windows operating system and Windows Defender up-to-date. To check for updates, go to Settings > Update & Security > Windows Update.

2. Restart Your Device

If there was a recent problem with Windows Defender performing a scan or downloading updates, it may be related to temporary files or processes that can interfere with proper operation. In this case, restarting your device can help clear out any stale information or processes that may be causing the issue.

3. Run a Scan

If you encounter any issues with Windows Defender, it is important to make sure that it is functioning properly. To do this, you can run a scan using the Windows Defender Security Center. To access the Security Center, press the Windows key on your keyboard, type “Defender”, and then select Windows Defender Security Center. From here, you can choose to run a Quick scan or Full scan, depending on your needs.

4. Check the Event Viewer

The Event Viewer is a tool that can help you diagnose errors and warnings with Windows Defender. To launch the Event Viewer, press the Windows key on your keyboard, type “Event Viewer”, and then select the Event Viewer application. In the left pane, you will see a list of logs. Double click on the “Application” log to open it.

From here, expand the “Windows Logs” section and then select “Application”. Any errors or warnings related to Windows Defender will be listed here, along with the corresponding error code which can help you troubleshoot the issue.

5. Check Firewall Settings

If you are having trouble with Windows Defender not starting up or running scans, it is important to check your firewall settings. Sometimes, third party firewalls can block Windows Defender from functioning properly. To make sure Windows Defender is not being blocked by your firewall, open the Windows Defender Security Center and click on the “Firewall & Network Protection” option.

In the right pane, make sure all of the listed items are set to “Allow”. If they are not, adjust the settings accordingly. You may also need to make sure that Windows Defender is allowed access through your router’s firewall settings.

6. Use a Malware Scanner

If you have exhausted all of the above steps and are still encountering issues with Windows Defender, it is possible that the issue may be caused by malware or other malicious software. To scan for potential malicious software, you can use an alternate anti-malware scanner such as Malwarebytes or SUPERAntiSpyware to scan your system for any potential threats.


Troubleshooting issues with Windows Defender can be a daunting task due to its complexity. However, following the above steps can help you identify the cause of the issue and take the appropriate steps to resolve it. Before attempting any of the above steps, it is important to make sure you have a reliable backup of your system in case something goes wrong. Also, if you are unsure of your technical prowess, it is best to consult an IT professional before attempting any of the above steps.