Is your Windows Defender turned off? Are you looking for comprehensive solutions to this problem?

Windows Defender Antivirus Not Turning On Windows 10
Windows Defender Antivirus Not Turning On Windows 10

Windows Defender Antivirus Not Turning On Windows 10, this post will show you how to repair Windows Defender in Windows 11/10/8/7 so that your computer is virus-free. In addition, we will introduce professional backup software for PC protection.

Windows Defender not turning on in Windows 10 can be caused by a variety of issues, such as having another security software installed that interferes with Defender, incorrect time and date settings, or being on an older version of Windows 10. To fix this issue, users should uninstall any third-party antivirus software

Video: How to Fix Windows Defender Not Turning On 

Fix Windows Defender Not Turning On 


Windows Defender (also known as Windows Defender Security Center in Windows 10 1703 or later) is an antivirus program that is fully integrated into Windows. It can protect your computer in real-time from various threats such as spyware, malware, and viruses. This program will stop potential threats after scanning them.

However, many users have reported that when they click on the Turn on the button, their Windows Defender cannot be turned on for virus defense in Windows 11/10/8/7.

Windows Defender Antivirus Not Turning On Windows 10

In addition to the case where Windows Defender could be turned off via group policy, some users reported that Windows Defender antivirus crashes and cannot be opened, or that Windows Defender antivirus cannot be opened after uninstalling Avast, Bitdefender, McAfee, or AVG.

Simply put, this problem could be caused by the installation of third-party antivirus software, a corrupted registry, software conflicts, and other factors. It is fairly common among Windows 7, Windows 8, Windows 10, and Windows 11 users.

So, what should you do if Windows Defender isn’t working properly? How do I successfully activate Windows Defender in Windows 8/10/7? Take your time! Get the complete solutions from the following section to assist you.

Further advice: If your Windows Defender is functioning normally but you need to disable it, watch the video below.


Method 1: Remove Third-Party Antivirus Software

If you have any third-party software installed on your computer, Windows will automatically detect it and shut it down. As a result, the first thing you can try is to turn off your other security programs for tamper protection.

Remove Third-Party Antivirus Software
Remove Third-Party Antivirus Software

If that doesn’t work, the best option is to completely remove them. In Windows 7, go to Control Panel > Programs and Features, or in Windows 11/10/8, go to Control Panel > Programs > Uninstall a program.

Then, to fix Windows Defender not turning on, locate your third-party program, right-click on it, and select Uninstall or Uninstall/Change.

Alternatively, you can uninstall your security applications using a professional removal tool, which will remove all files (including undetected files) and registry entries associated with the application, which may also prevent you from running Windows Defender.

Finally, restart your computer and relaunch Windows Defender to see if it can be activated for viruses, spyware, and other threat protection.

Method 2: Start the Security Center Service again.

Certain services must be enabled in order for Windows Defender to function properly. If those services are not functioning properly, Windows Defender will not start on Windows 11/10/8/7. So, follow the instructions to restart the required services, and then we’ll show you how to enable the Security Center service.

  • To open the Run box, press the Win and R keys on your keyboard.
  • In the box, type services.msc and press Enter.
  • Search for the Security Center service in the Services interface and right-click on it to select the Restart option.

After restarting this service, you can see if the problem with Windows Defender not starting has been resolved.

Method 3: Run an SFC Scan

If Windows Defender will not start on Windows 10/11/8/7 and encounters an unexpected error, there may be a problem with your system files. As a result, you can run an SFC Scan.

SFC, also known as System File Checker, is a Windows utility that allows you to scan for and restore corruptions in Windows system files. How do you scan your system files for missing or corrupted files? The steps are as follows.

Run an SFC Scan
Run an SFC Scan
  • In Windows 7/8/10, type cmd into the search box and right-click to run this program as administrator.
  • Enter the command line sfc /scannow into the Command Prompt window and press the Enter key. The utility will then begin a system scan. This procedure will take some time, so please be patient until verification is complete.
  • Exit the CMD window later to see if the Windows Defender unexpected error has been resolved.

You can use DISM scan instead to resolve the issue of Windows Defender Antivirus not turning on. To do so, follow these steps:

  • Run Command Prompt with administrative privileges.
  • Enter DISM /Online /Cleanup-Image /RestoreHealth in the pop-up window and press Enter to run this command line. This scan will also take some time; just wait and don’t interrupt it.

Method 4: Apply the Most Recent Update

Windows Defender or windows vista may not start due to an outdated Windows operating system. Some users reported that they were able to resolve the issue simply by installing the most recent Windows update – the most recent signature updates are required for Windows Defender to keep your PC secure.

MiniTool ShadowMaker is a professional backup software for Windows 11/10/8/7 that allows you to back up files into an image as well as sync files or folders to other safe locations. Now, download MiniTool ShadowMaker Trial Edition and install it on your computer to backup your files.

  • Start the MiniTool ShadowMaker Trial.
  • Go to Source > Folders and Files on the Backup page to select important files to back up for disbale windows.
  • Then, under Destination, select the location where you want to save the backup. An external hard drive, USB drive, NAS, or another storage device may be available here.
  • After making all of your selections, click the Back up Now button to begin the backup process.

Furthermore, you can fully utilize the Sync feature to synchronize your important files. How to Sync Folders in Windows 10 to an External Drive? 3 Tools Are Here demonstrates detailed operation steps.

Upgrade Windows OS

It is now time to install the most recent Windows operating system. How do I run a Windows update? Here’s how to do it:

  • Go to the Control Panel in Windows 7 and select Windows Update. Go to Control Panel > System and Security > Windows Update in Windows 8. To access the Windows Update interface in Windows 10, go to Settings > Update & security > Windows Update. Go to Settings > Windows Update in Windows 11.
  • Click the Check for updates button. Install any available updates and restart your computer.
  • The issue of Windows Defender not turning on may have been resolved after completing Windows updates.

Method 5: Modify Group Policy

Sometimes Windows Defender will not start in Windows 10/11/8/7 because it has been disabled by your group policy. This can be a problem, but you can easily fix it by changing the group policy in windows update.

Modify Group Policy
Modify Group Policy

Follow the steps below to get started:

  • By pressing the Win + R keys on the keyboard, you can access the Run dialog.
  • Enter gpedit.msc and click the OK button.
  • Navigate to Computer Configuration > Administrative Template > Windows Components > Windows Defender Antivirus in the left pane of the Local Group Policy Editor interface.
  • Double-click Turn off Windows Defender Antivirus in the right pane.
  • Choose Not Configured in the pop-up window, then click the Apply and OK buttons.

After you apply these changes, the problem of Windows Defender not working due to the group policy being turned off should be resolved, and you can use it to protect your computer.

Method 6: Change the Windows Registry

If you are unable to activate Windows Defender in Windows 11/10/8/7, the issue may be related to your registry. Then you can change it to resolve the problem.

  • In the Run window, type regedit into the text box.
  • Navigate to HKEY LOCAL MACHINESOFTWAREPoliciesMicrosoftWindows Defender in the Registry Editor interface.
  • Locate the DisableAntiSpyware button. If this key is not listed, right-click the blank, select New, and then DWORD (32-bit) Value.
  • Set its Value data to 0 by right-clicking on it.

After you’ve changed Windows Defender using Registry Editor, you can see if the problem with Windows Defender Antivirus not turning on has been resolved.

Method 7: Carry out a Clean Boot

When you start the Windows system in normal mode, many third-party applications may be running in the background of windows defender. These applications have the potential to cause software conflicts and interfere with Windows. As a result, Windows Defender cannot be activated in Windows 11/10/8/7.

You can repair Windows Defender by opening windows security and performing a clean boot. This method is very simple, and you can do it by following these steps:

  • Open the Run press windows and type msconfig into the textbox.
  • Go to the General tab in the System Configuration interface, select Selective startup, and uncheck Load startup items.
  • Tick Hide all Microsoft services and then click Disable all on the Services tab.
  • To restart your computer, click the OK and Restart button.

You have now been shown every possible solution to the problem of Windows Defender not turning on. Simply try each one one at a time to repair Windows Defender in Windows 11/10/8/7. If you think these methods are useful, you can also share them on Twitter to spread the word.


Can’t get Windows Defender to work on Windows 10/11/8/7? How do you activate Windows Defender in Windows 11/10/8/7? We have provided solutions to the problem of Windows Defender not turning on; simply try them one by one.

To keep your PC safe, use MiniTool ShadowMaker, a professional and dependable PC backup software, to automatically back up important files or the Windows system.


Questions and Answers

Why can’t I enable real-time protection in Windows Defender?

If the client is unable to enable real-time protection for Microsoft Defender, you may need to remove third-party antivirus or ensure that the Group Policy setting “Turn off Windows Defender” is not enabled for your client systems.

Can’t access the Windows Defender security center?

If Windows Security Center does not start because of a corrupted system file, a utility known as System File Checker can assist. It will scan your system for corrupted files and repair any that it finds. To begin the scan, open the command prompt as administrator, type “sfc /scannow” and press Enter.

Why is my virus protection disabled?

If your virus protection is shutting down or refusing to start, it’s possible that you have a software conflict on your PC, which can happen if you already have anti-virus software installed and try to install another.

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