• Windows Security sometimes triggers unexpected errors, blocks some apps or it may break down due to a bug. 
• Restarting your PC could help fix the issue sometimes, but if it doesn't, you would need to use more troubleshooting techniques. 
• Although the app is enabled by default in Windows 11, you may need to reinstall Windows Security to fix the problem. 

• Anti-theft support
• Webcam protection
• Intuitive setup and UI
• Multi-platform support
• Banking-level encryption
• Low system requirements
• Advanced anti-malware protection

With Windows 11, you do not need to download & install Windows Security separately, since it comes built-in with the OS.

Windows Security is the suite that comes built-in with Windows. So, when you install Windows 11, it gets automatically installed. It proves to be one of the most effective security solutions by Microsoft.

It includes an antivirus program called Microsoft Defender Antivirus which was known as Windows Defender Security Center in the older versions of Windows 10.

The app does a considerably good job in most situations with real-time protection for your PC from virus and malware attacks.

However, the app is prone to issues, for example, it may fail to open or may not work sometimes when you try to launch the app.

You may want to check first if the Windows Defender app is turned off and if enabling it may help fix the issue.

But, if the Windows Security is still not working, in such cases, you may need to re-install the app on your Windows 11 PC.

Before we move over to the solutions, let’s understand how to download the Windows Security app on Windows 11 when it fails to open.

How do I get Windows Security on Windows 11?

In most cases, you simply need to enable the components of Windows Security back again from the Settings app to have access to it. Here’s how to enable Windows Defender:

Click on Privacy & security on the left.

Next, on the right, click on Windows Security.

Now, click on Open Windows Security on the right.

For example, click on Virus & threat protection.

On the next screen, scroll down and click on Manage settings.

Now, go to Real-time protection and turn it on.

However, there are more Windows Defender components and so, you can access each of them to enable their features.

But, if the Windows Security app is missing from your Windows 11 PC, then you would need to reinstall it.

In the following section, we have listed some of the solutions that may help you to download & install Windows Security on your Windows 11 device.

How do I reinstall Windows Security in Windows 11?

1. Use Windows PowerShell

1.1 Install the Windows Security app

Right-click on the Start menu and select Windows Terminal (Admin).

Now, run the below commands one by one in the Terminal and hit Enter after each one: Set-ExecutionPolicy Unrestricted Get-AppXPackage -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}

This will disable the development mode for all the apps. Now, try to open the Windows Security app and it should work normally.

1.2 Repair and Reinstall Windows Security

Right-click on the Start button and select Windows Terminal (Admin) from the menu.

Copy and paste the below command in the Terminal and hit Enter: Get-AppxPackage Microsoft.SecHealthUI -AllUsers | Reset-AppxPackage

This will repair any issues for the situation, when the app is installed, but not installed correctly. Thus, helping you to reinstall the Windows Security app on Windows 11.

2. Restart the related service

Navigate to the Start menu, right-click on it and select Run.

Type in services.msc in the Run console search box and press OK to open the Service Manager.

Go to the right side, and under the Names, column look for the Security Center service.

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Each time you boot your PC, the Security Center service starts running automatically.

But if it fails to run at times, or gets disabled for some reason, you will be unable to open the Windows Security app on Windows 11.

Once you are done restarting the service, check if you can open the Windows Security app now.

3. Turn on AntiSpyware from the Registry

Before you proceed to make any changes to the registry editor, make sure you create a backup of the registry settings. This will help you recover any data that may be lost during the process.

Right-click on the Start icon and select Run to open the Run console.

In the search bar, type regedit and hit Enter to open Registry Editor.

Next, go to the right side and double-click on DisableAntiSpyware.

If the DisableAntiSpyware is not available, then right-click on a blank space, select New, and then select DWORD (32-bit) Value.

Rename the new DWORD Value as DisableAntiSpyware. Double-click to open it.

Now, the Edit DWORD (32-bit) Value will pop up. Here, set the Value data to 0.

Now, close Registry Editor and restart your PC. The Windows Security app should work now.

Sometimes, changes to the registry settings can turn off the Windows Security components. These could be accidental changes either by the user or by a third-party application on your PC.

For more solutions on how to install Windows Security on Windows 11, you can follow our detailed guide on Windows 11’s Security center not opening.

Besides, if you have a 3rd party antivirus software installed and running on your system, you can temporarily disable it, to stop it from interfering.

You can now check if you can open the Windows security app on your Windows 11 PC.

Why is Windows Security not working on Windows 11?

The Windows Security app not opening is a common issue, especially with the Windows 11 Insider builds. You would usually notice this issue after a Windows OS upgrade or randomly.

You may refer to our detailed guide on other Windows Security issues. While it’s a Windows 10 guide, it works on Windows 11 too.

You may find that the Windows Security app is not installed on Windows 11, when:

• System files are corrupted
• Related services are not running
• There’s is interference from a 3rd party antivirus
• Windows updates are pending
• System settings are altered due to an internal glitch
• The registry settings are modified

In most cases, the Windows Security not working in Windows 11 issue pops up on the latest build. So, if you have recently upgraded to Windows 11, you may encounter this issue.

You can simply follow the above methods or refer to our guide on Windows security not installed on Windows 11 for more solutions.

If Windows Security is still not opening on your Windows 11 PC, you can leave your comments below in the comments box and we may come up with a workaround.

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