If you don’t update Windows Defender, then it will fail to scan your PC for viruses, malware, spyware, and other malicious programs. Thus, you might have tried to update this built-in security feature for your PC. 

Now the problem arises when this update fails despite a proper internet connection. This article explains how to update Windows Defender so that your computer is protected from external threats. 

Solutions to Fix Windows Defender Won’t Update Issue

See what to do if the Windows Defender update doesn’t work on your PC. 

Solution 1: Use Windows Update

If Windows Defender update fails due to connectivity problems, then try to update it by using Windows update. For this, you need to install the pending updates for your Windows Operating System as discussed below:

  1. Go to the Start menu and open the Settings window. Windows 10 users can use the Windows key+I shortcut to access Settings directly. 
  2. Click ‘Update and Security’ and choose ‘Windows Update’ in the left pane. 
  3. Click the ‘Check for Updates’ button and let Windows scan for pending updates. 
  4. If updates are available, then click the ‘Install’ button to get them on your PC. 
  5. After installing the Windows updates, try to update Windows Defender. 

[Note: Windows update doesn’t erase saved data generally. Still, we would recommend you to backup your PC before updating Windows. You can choose a professional backup software or create a backup manually. ]

Solution 2: Use Command Prompt

  1. Right-click on the Start menu to access the WinX menu and select ‘Command Prompt(Admin)’ from it. 
  2. If you aren’t using Windows 10, then type ‘cmd’ into the Windows search bar. 
  3. Right-click cmd in the search result and select ‘Run as Administrator’ from the context menu. 
  4. Copy-paste ‘cd /d “\Program Files\Windows Defender’ into the elevated command and hit ‘Enter.’
  5. Now type ‘exe -signatureupdate’ into a new command and press ‘Enter’ on the keyboard. 
  6. The above command automatically downloads Windows Defender update and installs it on your PC. 
  7. Run the updated Windows Defender to ensure that it is scanning your PC correctly. 

Solution 3: Uninstall Third-party Antivirus

Some third-party antiviruses seem to conflict with activities like Windows Defender update. Therefore, uninstall such antivirus and try to fix the Windows Defender Update failed issue. 

  1. Go to the Start menu and search for Control Panel. 
  2. Open the Control Panel window and click the ‘Programs and Features’ link. 
  3. Whereas, Windows 8 and 10 users need to choose ‘Programs’ after accessing the Control Panel. 
  4. Now, click the ‘Uninstall a Program’ link and locate your third-party antivirus. 
  5. Right-click on the antivirus and select ‘Uninstall’ or ‘Uninstall/Change’ from the drop-down menu. 
  6. Click ‘OK’ to confirm the uninstallation and restart the system if prompted. 
  7. After completing the entire process, update Windows Defender. 

[Note: If it seems difficult to uninstall the antivirus, then do the work with one software removal tool.]

Solution 4: Restart the Security Center Service

Certain services are necessary to update and use Windows Defender correctly. Security Center service is one such service that you need to restart as explained below:

  1. Press the Windows logo key and ‘R’ at the same time to open the Run application. 
  2. Type ‘services.msc’ into the search field of the Run application. 
  3. Look for Security Center among the list of services running on your PC. 
  4. Click the Security Center service and choose the ‘Restart’ option. 
  5. Now check whether you can update Windows Defender easily or not. 

Solution 5: Use the System File Checker Tool

Windows Defender will not update if there are corrupted files on your PC. Thus, you need to identify those files and fix them immediately with System File Checker, a built-in tool for Windows.

  1. Type ‘cmd’ into the Windows search bar and press ‘Enter.’
  2. Right-click on ‘cmd’ in the search result and select ‘Run as Administrator’ to open an elevated command. 
  3. Type ‘sfc/scannow’ into the elevated command and hit ‘Enter’ to launch the System File Checker tool. 
  4. System File Checker scans for corrupted files and fixes them automatically. 
  5. You will receive a confirmation message once the corrupted files are fixed. 
  6. Then you can try to update Windows Defender. 

Solution 6: Change Your Group Policy

Windows Defender update might have been disabled by your Group Policy. So, change the Group Policy by using the following steps:

  1. Press Windows key and ‘R’ together to initiate the Run application. 
  2. Type ‘gpedit.msc’ into the search field of the Run application and click the ‘OK’ button. 
  3. Navigate to ‘Computer Configuration’ in the Local Group Policy Editor Interface and click on ‘Administrative Templates.’
  4. Choose ‘Windows Components’ and select ‘Windows Defender Antivirus’ under it. 
  5. Select ‘Not Configured’ on the next window and tap the ‘Apply’ button. 
  6. Click ‘OK’ to save the changes and close the Local Group Policy Interface. 
  7. Try to update Windows Defender to ensure that it is working correctly.  

Solution 7: Set Windows Defender Service as Automatic

  1. Open the Run application as explained in the previous solution. 
  2. Type ‘services.msc’ into the Run dialog box and click ‘OK’ to find the list of services running on your PC. 
  3. Locate Windows Defender antivirus service, right-click on it and choose ‘Properties’.
  4. Check whether the Service Status is ‘Running’ or ‘Stopped.’
  5. If the service status is ‘Running,’ then go to ‘Startup Type’ and set it as ‘Automatic.’
  6. Click the ‘Start’ button and hit the ‘Apply’ button to let the changes take effect. 

[Note: You can’t use this method if the Service Status is ‘Stopped.’]

Solution 8: Modify the Windows Registry

It is not advisable to edit the Registry without professionals. But, we have explained the process for your convenience. 

  1. At first, open the Run application and then type ‘regedit’ in it. 
  2. Navigate to ‘HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender’ in the Registry Editor interface. 
  3. Locate the ‘DisableAntiSpyware key’ among the list of Registry entries. 
  4. If the aforesaid key is not listed, then right-click on a blank space and select ‘New’ to create the key. 
  5. Right-click on the key and set its ‘Value Data’ to ‘0.’
  6. Now see whether it’s possible to update Windows Defender or not. 

Solution 9: Perform a Clean Boot

If nothing works, then you can perform a clean boot as a last resort. It is a simple method that involves the following steps:

  1. Press Windows key and ‘R’ simultaneously to launch the Run application. 
  2. Type ‘misconfig’ into the Run dialog box and click ‘OK’ to open the System Configuration window. 
  3. Navigate to the ‘General’ tab and choose ‘Selective Startup.’
  4. Uncheck ‘Load Startup Items’ and go back to the ‘Services’ tab.
  5. Hide all Microsoft services and select the ‘Disable All’ option. 
  6. Click the ‘OK’ button and restart the PC. 
  7. Hopefully, now Windows Defender will update without an issue. 

If none of the solutions can fix Windows Defender not updating issue, then you have to manually download the latest update package for Windows Defender.