How to Fix Windows Defender won’t open in Windows 11 [METHODS]

Microsoft has developed protection software for its Windows Operating System also know as Windows Defender. It is pre-loaded into every version of Windows and is available for no extra subscriptions or pay walls like other manufactures.

Although, Windows Defender is almost as old as Windows operating system, it has gone through a complete transformation in those years. Back in the days, Defender was not considered as reliable protection software because it’s clunky interface and decade old working mechanics that did work when protecting the system with newer harmful things.

Now the tables have turned, Windows Defender is used by millions of users and is gaining more popularity every day. Even though it has completely changes the bugs and errors with it haven’t changed much. Many users have reported that Windows Defender won’t open in Windows 11. For that reason we have listed all the possible fixes and workarounds below.

Method 1: Reboot Windows 11

The reason why Windows Defender is not opening is because of a temporary bugs or glitches in your system. To fix this you just have to perform a simple reboot of your Windows 11. This will get rid of those bugs and glitches.

Method 2: Uninstall 3rd Party Antivirus

Running Windows defender with other security app is notorious for creating differences and causing such issues. This means you can only use single protection software on your computer system. In-fact those third party app are not as trustworthy as Windows Defender. To fix the issue you have to remove those applications and setting up Windows Defender as default. To do so follow these steps:

  1. Open Settings application from Start menu.
  2. Go to Apps from the left side.
  3. Now move to Apps & Features.
  4. Find the 3rd party application and click on 3-dot
  5. Select Uninstall to remove the program completely.

Method 3: Reset and Repair Windows Security

Another viable method to fix the issue is to repair and reset Windows Security Application. Steps are given below:

  1. Open Start menu and select Settings
  2. Navigate to Apps then move to Apps & features.
  3. Locate Windows Security program and click 3-dot button beside it.
  4. Choose Advanced Options.
  5. First click Repair Wait for the process to complete and check if the issue persists.
  6. It yes then, click Reset

You can also reset using PowerShell. To do so

  1. Right click on Start icon.
  2. From the list select Run PowerShell (Admin).
  3. Click yes when prompted.
  4. Now type Get-AppxPackage Microsoft.SecHealthUI –AllUsers | Reset-AppxPackage.
  5. Press Enter after the command and wait for it to finish.
  6. Close the Windows and check if the issue is still there.

Method 4: Reinstall Defender via PowerShell

  1. Open PowerShell with administrative privileges. (Refer above steps on how to do so)
  2. Type these command lines and press Enter after each.
  • Set-ExecutionPolicy Unrestricted
  • Get-AppxPackage –Allusers | Foreach {Add-AppxPackage –DisableDevelopmentMode –Register “$($_.InstallLocation)\AppXManifest.xml”}
  1. Reboot your computer after the completion.

Method 5: Run System File Checker and DISM

If the registries are damaged or some system files are corrupted then this might explain the issue. System File Checker (SFC) and DISM is command line tool in-built into Windows Operating System to find and fix system issue. To execute these commands, follow these instructions:

  1. Press Win + S to open Search
  2. Type cmd and press enter.
  3. Right-click on Command Prompt from Best matches list.
  4. Select Run as administrator.
  5. In Command Prompt window, type sfc /scannow and press Enter key.
  6. Wait for it complete.
  7. Again in Command Prompt, type DISM /Online /Cleanup-Image /ScanHealth
  8. After it is done, restart your computer and check for the issue.

Using SFC and DISM command line tool is not very efficient and effective in finding hidden or damaged complex system files. Therefore we recommend you to use PC Repair Tool, it will automatically scans your whole system looking for corrupted system files, missing DLLs or damaged registries and fix them using its complex and advanced algorithmic logic system.


If you are one of those users who recently upgraded to Windows 11 and now facing issue like Windows Defender won’t open in Windows 11 then don’t worry, we have listed all the possible methods and solution you can use and fix the issue.