Windows Defender won’t update [BEST FIXES]

Milan Stanojevic
by Milan Stanojevic
Deputy Editor
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Windows Defender won’t update

A good number of Windows users have raised concerns that Windows Defender won’t update on their computers.

Most of these queries have to do with Windows Defender failing to update virus definitions, and this usually happens when their internet connection is good.

Sometimes even the Windows Update feature is affected as it fails to update the system.

While using Windows Defender, you may receive a message with regards to definition updates when opening the service, or when you try to check for updates and it says they cannot be checked, downloaded or installed.

Windows Defender is the default, pre-installed antimalware software built into Windows 10 OS, to protect users from malware like adware, viruses, worms, Trojans, Rootkit, Backdoor, ransomware and spyware, among other emerging threats.

In this case, the service should work well in the background notifying users of any detected malware or when something is wrong.

In some cases, however, you may come across issues such as this, when Windows Defender won’t update, or the update fails. Usually, there are three ways to update it:

  • From the Windows Defender Update Interface
  • From Windows Update
  • From Manual Download via the Microsoft Malware Protection Center (MMPC) website

We’ve written extensively about Windows Defender issues before. Bookmark this page in case you need it later.

If you’re getting the Windows Defender won’t update problem, try the solutions listed below to resolve the issue.

Note: If your computer is part of a company network, or it is managed by an admin, they’ll configure updates through local network drives or set policies to update after approval. Check with your network admin first.

FIX: Windows Defender won’t update

  1. Preliminary fixes
  2. Manually install update definitions
  3. Verify that you have all required Windows Update files
  4. Set Windows Defender service as automatic
  5. Run an SFC Scan

1. Preliminary fixes

  • Check if you have other security software installed, as these will turn off Windows Defender and disable its updates. Uninstall your current anti-malware software
  • Check for updates in Windows Defender Update Interface and try Windows Update if it failed. To do this, click StartProgramsWindows Defender>Check for Updates Now.
  • Install all updates that may be pending and restart your computer, then try the Windows Defender update again. Set Windows Defender to automatically get updates (it gets this as part of Windows Updates)
  • Run Windows Update troubleshooter

2. Manually install update definitions

Microsoft usually delivers updates through Windows Update, Automatic Updates or Windows Server Update Service (WSUS).

In some cases, Windows Defender won’t update because of problems with these services.

In this case, update the definitions manually as this could be caused by Windows Update. To do this:

  • Go to Windows security portal
  • Follow the instructions to download and install the definition updates
  • If you cannot install manually or still get update errors, there are other things hindering it so contact Microsoft tech support for further assistance

Note: if you were able to install updates manually, the issue is caused by a Windows Update problem.

Solve Windows Update issues by using these great tools!

3. Verify that you have all required Windows Update files

  • Open Windows Update website
  • Install all recommended updates
  • Review the Windowsupdate.log file for error messages by clicking Start, then type %windir%windowsupdate.login the Search box, and then press enter.
  • Go to Windows Help and How-to web page and enter the keywords describing the problem from the log file you found

4. Set Windows Defender service as automatic

  • Right click Start and select Run

Windows Defender won’t update

  • Type services.msc and press enter
  • Right click Windows Defender antivirus service

Windows Defender won’t update

  • Click Properties
  • Ensure that Service Status is running

Windows Defender won’t update

  • Ensure Startup type is Automatic (if not, select Startup type as automatic and click Start)

Windows Defender won’t update

  • Click Apply then click OK

Windows Defender service won’t start? Check out this detailed guide to fix the problem in no time!

5. Run an SFC Scan

This will check whether there are corrupted system files that cause Windows Defender not to update. To do this,

  • Click Start
  • Type CMD in the search box
  • Right click Command Prompt and select Run as Administrator

Windows Defender won’t update

Windows Defender won’t update

Let us know if any of these solutions worked by leaving a comment in the section below.


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