Written by
Yuri ZhangIf Windows Defender also known as Microsoft Defender is missing or unavailable on our Windows system, it can leave our PC vulnerable to threats.
If you are interested in Windows Defender by itself, read Windows Defender for Everyone and Windows Defender Application Guard. Now let's tag along with the solutions and reasons behind the Windows Defender app isn't working, displaying a blank page, or showing "Page Not Available".
1. Ensure Microsoft Defender is installed in Windows
If Microsoft Defender is uninstalled or missing, you cannot access its protection features. Here are steps to verify and reinstall the Windows Defender app:
- Press Win + I to open Settings.
- Navigate to Apps > Installed apps (or Apps & Features).
- Search for Microsoft Defender. If it's missing, follow the next step to reinstall it.
- Press Win + X > Windows Terminal (Admin) to open PowerShell as Administrator.
- Run the following command:Get-AppxPackage Microsoft.SecHealthUI -AllUsers | Reset-AppxPackage
- Restart your PC and check again.
Tips: Except for using PowerShell, you can use Windows Update to ensure Microsoft Defender is installed and up-to-date, as it is typically included in Windows updates.
2. Check Windows Services to fix Windows Defender
Windows Defender relies on certain services (like Windows Defender Antivirus Service) to function. If these services are turned off or disabled, Defender won't be available.
- Press Win + R, type services.msc, and press Enter to open Windows Service.
- Look for Windows Defender Antivirus Service and Security Center.
- If they are disabled, right-click on each, set Startup Type to Automatic, and click Start.
Share these and continue to practice the following if Microsoft Defender is still infeasible.
Tips: Third-party antivirus software may disable Windows Defender to avoid conflicts between the two. The solution is to go to Control Panel > Programs and Features. Then uninstall any third-party antivirus software (e.g., McAfee, Norton, etc.) and restart your PC.
3. Use Command Prompt to repair Windows Defender
Sometimes, system corruption or issues with system files can prevent Windows Defender from working. Running system repair tools can help restore its functionality.
- Press Win + X > Command Prompt (Admin) to open Command Prompt as Administrator.
- Copy these commands one by one and press Enter:sfc /scannow
- DISM /Online /Cleanup-Image /RestoreHealth
- Restart your PC after the scans are complete.
4. Check if Group Policy disables Microsoft Defender
Group Policy might disable Windows Defender to prevent it from running on your system, often in enterprise or managed environments. If it's disabled, you'll need to enable it. Here's how:
- Press Win + S and search for Windows Security.
- Click on Virus & threat protection.
- If you see a message saying "Your IT administrator has limited access", it means that Windows Defender has been disabled via Group Policy.
You can enable Defender via the Group Policy Editor by reading the following fifth solution. If you don't see this option, your version of Windows might not have it.
Note: Windows Defender is supported on Windows 7 (with Service Pack 1 and above), Windows 8/8.1, Windows 10/11 (all editions), as well as Windows Server editions, but its features and capabilities vary by version.
5. Verify Group Policy Settings (For Windows Pro/Enterprise)
The Group Policy Editor allows you to control various system settings, including whether or not Microsoft Defender is enabled. If a policy has disabled it, you'll need to modify the settings. Here's how:
- Press Win + R, type gpedit.msc, and press Enter.
- Navigate to Computer Configuration > Administrative Templates > Windows Components > Microsoft Defender Antivirus.
- Ensure that "Turn off Microsoft Defender Antivirus" is set to Not Configured or Disabled.
Changing this setting to Disabled or Not Configured ensures that Defender is allowed to run.
Final thought
If these steps do not resolve the issue, it might help to know your specific version of Windows (press Win + R > winver) to tailor further solutions. In many cases, one of the above fixes should get Microsoft Defender back up and running, ensuring that your PC remains secure from outside threats. If you have further problems, feel free to share and discuss.
More Windows tricks:
How to Update Device Drivers on Windows System
Fix There Are No More BitLocker Recovery Options on Your PC
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