Fix – Windows Defender Won’t Update


Are you facing the Windows Defender won’t update issue? Fortunately, different ways exist to fix this problem and get Windows Defender working. However, if you have a security solution like T9 Antivirus installed and running, you can forget about this issue and keep your Windows secure using this best security application for Windows.

How to fix Windows Defender is unable to update?

1. Basic fixes

Before getting into more technicalities, try these basic steps to fix the Windows Defender update issue.

  • If you have an additional security application running, check Windows Defender to ensure it has not disabled the updates. If it interferes with a pre-installed security application, uninstall the third-party antivirus solution.
  • Manually check for Windows Defender Update; try downloading and installing available Windows Update. If the update fails, from the notification area, click the shield icon > select Virus & threat protection > Check for updates.
  • Install all updates and reboot the system. After that, try updating Windows Defender and enable Windows Defender to update it automatically.
  • Run the Windows Update troubleshooter.

Also Read- Do You Need Antivirus for Windows 11, 10

If the preliminary fixes do not help, try the other fixes explained below.

2. Try an alternative antivirus solution

When Windows Defender fails to function as it is supposed to, consider using an alternative like T9 Antivirus. To use this best security tool and forget about all update errors, follow these steps:

1. Download and install T9 Antivirus.

2. Run the best antivirus for Windows

T9_Home Screen
3. For better security, the tool offers different scanning modes. Select one from the given choices –

Quick Scan – check the recent and default folders for threats.

Deep Scan – performs an in-depth scan of folders, subfolders, files, hidden files, and every other data saved on the PC.

Custom Scan – allows users to specify the drive to scan for malware, ransomware, trojan, adware, and other nasty threats.

T9 Antivirus_Quick Scan

4. Select it and start performing the scan.
5. To protect you, as the antivirus detects threats, it will quarantine them.

T9_Quarantine_Deep Scan
6. Click Finish when the scan stops > see the scan summary and restart your computer to apply changes.
T9_Antivirus_scan finished

This professional security tool performs its job in the background. Moreover, it comes with real-time protection, malware protection, scans startup items for infection, keeping you safe from ransomware, spyware, malware, adware, identity theft, and other viruses. It is easy to install and straightforward to use.

Must Read- How Can An Antivirus Speed Up Your PC

3. Manually install update definitions

1. Visit the Windows security portal
2. Follow on-screen instructions to download and install definition updates
3. If you cannot manually get the updates, set it to automatic.

4. Set Windows Defender service to Automatic

1. Press Windows + R and open the Run window.
2. Type services.msc > Enter
3. Right-click Windows Defender Antivirus Service > PropertiesWindows Defender Antivirus Service
4. Make sure the Service Status is running.

Arrow on Stopped button
5. Ensure the Startup type is Automatic (if not, select Automatic from the drop-down menu > hit Start.

Select Startup type
6. To save changes, click Apple > Ok.

5. Verify your system has all Windows Update Files

If you don’t have all the required Windows update files, Windows Defender may not update. Therefore, you need to verify that you have all Windows Update files.

To do so, follow these steps:

1. Visit the Windows Update Website.
2. Next, install recommended updates into your system.
3. Review the Windowsupdate.log file for error messages. To do so, click on Start and type %windir%windowsupdate.login into the search box. You will now get keywords explaining the issue.
4. Now visit the Windows Help and How-to page and type the keywords (explaining the issue) you got from the log file.

6. Run an SFC Scan

1. Run elevated Command Prompt
2. Type sfc /scannow > Enter.

Remember there is a space between sfc and /

Type sfc /scannow

3. This command will check Windows for corrupt system files and will fix them.

7. Update Windows Defender via Command Prompt

When Windows Defender fails to update independently, consider using Command Prompt. To do so, follow the steps below:

1. Open elevated Command Prompt.
2. Type cd /d “\Program Files\Windows Defender” > Enter in the Command Prompt administrator windows.
3.  Next, type mpcmdrun.exe -signatureupdate > Enter.
4. The above commands will start Windows Update.

8. Run Windows Update Troubleshooter

1. Press Windows + I > Update & Security.
2. Click Troubleshoot from the left pane > Additional troubleshooters.

recommended troubleshooting
3. Select Windows Update > Run the troubleshooter.

Run the troubleshooter
4. Follow on-screen instructions.
5. When done, click Close the troubleshooter.
6. Restart the system.

This should fix the issue.

Must Read- How Often Should You Update Your Antivirus Software?

Wrap Up

The above steps will certainly help fix Windows Update Error on Windows. However, if you don’t like using Windows Defender because of the way it behaves, give T9 Antivirus a try. This excellent and powerful antivirus tool will help identify and clean malware, spyware, adware, ransomware, trojans, and other threats.

Let us know how you find the post. Also, if you have any solutions, do share them with us in the comments section below.


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About The Author

Preeti Seth
Preeti Seth

A UX writer who loves explaining technical details in a clear, crisp, and concise manner. She loves writing about technical troubleshooting, How-To's, product reviews, etc. In her free time, she loves reading, meditating, and traveling.

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