WINDOWS DEFENDER

Question

Can't update Windows Defender 'signatures'. Need help. Thanks.

Answer 1

Hi,

What happens when you install Defender updates? Was there an error message?

Meanwhile, please try to update the definitions using the offline package.

Download mpam-fe.exe from https://go.microsoft.com/fwlink/?LinkID=121721&arch=x64

Run the package. You may not see any output when you run that file.

Once done, run PowerShell (admin) and run the following command:

get-mpcomputerstatus

get-mppreference

Copy the output and post it in your reply.

Answer 2

Try this order for Windows Defender signature update failures:

1. Reset internet settings.
   • Close all apps.
   • Open inetcpl.cpl from Start.
   • Go to Advanced > Reset > confirm Reset.
   • Try the Defender update again.
   • Note: this can remove temporary files, cookies, browsing history, and saved online passwords.
2. Check date and time.
   • Go to Start > Settings > Time & language > Date & time.
   • If the error code is 0x80072f8f, incorrect date or time is a common cause.
3. Reset the Windows Update cache.
   • Open services.msc.
   • Select Windows Update > Action > Stop.
   • Open Command Prompt as administrator and run:

cd %windir%
ren SoftwareDistribution SDTemp
exit

• Go back to services.msc.
• Select Windows Update > Action > Start.

4. Reset Defender definitions.
   • Open Command Prompt as administrator and run:

cd \
cd program files\windows defender
MpCmdRun -RemoveDefinitions -all
exit

• Restart the PC.
• Try updating again.

5. Try a manual definition update.
   • Download and install the latest definitions from: https://www.microsoft.com/en-us/wdsi/defenderupdates
6. If updates still fail, check these common causes:
   • Another non-Microsoft antivirus product is installed and has disabled Microsoft Defender Antivirus.
   • Network, firewall, or proxy access is blocking Defender update URLs.
   • Windows Update is having issues.
7. PowerShell option.
   • In an elevated PowerShell session, Update-MpSignature updates antimalware definitions.

If the issue continues after these steps, contact Microsoft support.

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• Troubleshoot Windows Defender or Endpoint Protection client
• Troubleshoot Windows Defender or Endpoint Protection client
• Troubleshoot Microsoft Defender Antivirus Security intelligence not getting updated
• Update-MpSignature