Windows Defender is more than just an antivirus program. It also offers many other protections, such as ransomware protection, browser-based protection against malicious websites, and on-demand file scans.

It does this by running several underlying services. These services start automatically if Windows Defender is running. Generally, there is no need for the user to intervene.

Windows Defender does not start

Windows Defender is an essential service that runs on Windows 10. If you want to use Windows Defender, you can’t stop this service. If the service doesn’t start, Windows Defender won’t either. You can do this if Windows Defender does not start.

1. Disable third-party antivirus programs

One of the main reasons why Windows Defender may not work or its services may not start is because you have another antivirus program on your system. Normally, Windows Defender does not work when another antivirus is running.

Remove the third-party antivirus and restart the system. If the service and Windows Defender do not work, uninstall the third-party antivirus and restart the system.

2. Check the Windows Defender startup settings

Windows Defender should start automatically when you start the system. However, if the service is configured to start manually, Windows Defender will not run automatically.

  1. press The Win + R hotkey opens the driving screen.
  2. In the competition box Come in services.msc and press the Enter key.
  3. Search Windows Defender Firewall Service and double-click it.
  4. in In the Startup type drop-down list, select Automatic.
  5. Click on it Home key.

3. Edit the registry settings

Windows Defender can be disabled from the registry. If it is disabled in the registry, the Windows Defender service will not start. You must first activate it from the registry.

  1. press The Win + R hotkey opens the driving screen.
  2. In the competition box Come in regedit and press the Enter key.
  3. Mene this key: HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesSecurityHealthService
  4. Double-click the output value and set it to 2.
  5. Restart the system.
  6. Activate Windows Defender.
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4. Check the environment variables

Users have the freedom to modify their environment variables. However, users should not delete any paths added by default. Verify that the path to the% ProgramData% variable is set correctly. If not, it will prevent Windows Defender from working.

  1. Open File management.
  2. Attach this explorer shell:::{BB06C0E4-D293-4f75-8A90-CB05B6477EEE} in the address bar and press the Enter key.
  3. Click Advanced system settings in the left column.
  4. Mene Advanced tab and click Environmental variables.
  5. Select% ProgramData% and he should click C: ProgramData. If not, change it and update the path.
  6. Click OK and restart the system.

5. Edit the ProgramData authorization

The ProgramData folder is an important system folder. If the permissions on the folder have changed, Windows Defender will be affected.

  1. Open File management.
  2. Open C position or any Windows drive.
  3. Right-click ProgramData folder and select properties from the shortcut menu.
  4. Mene Security tab.
  5. Click Advanced basically
  6. Disable all inherited licenses.
  7. Click Apply and restart the system.

Note: ProgramData is a hidden folder. You must allow hidden items to use them.

6. Perform a system scan

If one of the Windows 10 files is damaged, Windows Defender will not start. You can use the SFC scan tool to find and repair corrupted files.

  1. Open Command prompt with administrator privileges.
  2. Throw it Order: scf /scannow.
  3. Let the command run and activate Windows Defender.

7. Install the pending updates

Windows Defender regularly receives virus definition updates. If these updates are not installed, you may have problems running antivirus software.

  1. Open Apply settings with the Win + I hotkey.
  2. Mene Update and security.
  3. choose Windows Update tab.
  4. Click Check for updates.
  5. Install available updates and restart the system.
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8. Create a new user

It is possible that the current user’s files have been irreparably damaged. The easiest way to check this is to create a new user and activate Windows Defender. If this is enabled, you can switch to a new user, set them up as an administrator, and delete the old account.

  1. Open Apply settings with the Win + I hotkey.
  2. Mene Account.
  3. Care about Family and other people.
  4. Click Add someone else to this computer.
  5. Determine a new local account.
  6. Log in to a new account and activate Windows Defender.

9. Reset Windows 10

If a new user cannot be created, it is time for the kernel option; restore Windows 10. You keep all your files, but the applications are removed.

  1. Open Apply settings with the Win + I hotkey.
  2. Mene Update and security.
  3. choose Restore tab.
  4. Click Start with Restore this computer.
  5. Choose an option that allows you to keep your files.
  6. Follow the instructions on the screen and the computer reset.


Your computer should not be without an antivirus program. If Windows Defender isn’t running and you don’t have another antivirus program, your system may be infected. The above fixes should allow Windows Defender to work.

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