Is there any way to fix Windows Defender Threat Service from crashing?

Joanne 40 Reputation points
2026-08-18T09:30:11.9833333+00:00

Hello everyone,

This morning I've been dealing with Windows Defender trying to scan my laptop for viruses after downloading a dataset on an academic project of my master's. While scanning, I got the following error message, I am in fear of getting a virus just by a service malfunctioning.

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This happens every time I am trying to restart Windows Defender service.

Checked services.msc and Windows Defender Antivirus Service is set to 'Running' and 'Automatic'. While right-clicking on the service. all options are greyed out by constantly getting it to start.

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In the meantime, I also get a 'your IT administrator' message or something I can't recall at the moment. I did nothing wrong, just troubleshooting a service that crashes.

Microsoft Defender service crashes near the end of the scan.

What I have done so far:

  • restarted laptop, same issue to no avail
  • scanning via the Terminal on DISM and SFC scans, both completed successfully
  • killed Windows Security window via Task Manager
  • got Windows Defender service run via services.msc (this is what caused the graying out of the operations in services window)
  • 'restarted' Windows Defender service multiple times while trying to scan laptop for viruses
  • attempted full scan, no results yet

After completing all these, the only solution is turning to a third-party antivirus as it's a dead end in my case. However, a third party antivirus may cause my laptop to overheat and conflict with Windows Defender.

Any help or feedback are greatly appreciated, thank you in advance!

Microsoft Security | Microsoft Defender | Other

2 answers

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  1. J 1 5 Reputation points
    2026-08-19T07:26:26.3533333+00:00

    I have just updated, ran a quick scan, worked fine, no issues.

    I'm hoping it has been resolved, thank you Microsoft.

    Intelligence version is....1.457.239.0

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  2. AI answer

    2026-08-18T09:30:44.3533333+00:00

    Yes. Based on the symptoms, the best supported path is to verify Defender components, remove any conflicting antivirus, then reset the Defender engine and platform.

    1. Check Defender services in an elevated PowerShell window:
    Get-Service WinDefend, WdBoot, WdFilter, WdNisSvc, WdNisDrv, SecurityHealthService, wscsvc | Format-Table -Auto DisplayName, Name, StartType, Status

    Expected state includes:

    • WinDefend = Automatic, Running
    • SecurityHealthService = Manual, Running
    • wscsvc = Automatic, Running
    • WdFilter = Boot, Running
    • WdBoot can be Stopped after boot and that is normal

    If WdFilter, WdNisDrv, WdNisSvc, or WinDefend are stopped, continue with the reset steps below.

    1. Rule out malware first. Run Microsoft Safety Scanner.
    2. Do not install a third-party antivirus unless necessary. If any non-Microsoft antivirus is installed, uninstall it first. On Windows 10 and Windows 11, a non-Microsoft antivirus can cause Microsoft Defender Antivirus to be turned off automatically, or to run in passive mode when Defender for Endpoint is present.
    3. Reset Defender definitions and platform. Open an elevated Command Prompt and run:
    MpCmdRun.exe -RemoveDefinitions -All
MpCmdRun.exe -ResetPlatform
    1. Back up Defender policy settings before removing them. This is a registry change. Incorrect changes can affect security settings. In an elevated PowerShell session, run:
    New-Item -Path "C:\DefenderTemp" -ItemType Directory; Invoke-Command {reg export 'HKLM\SOFTWARE\Policies\Microsoft\Windows Defender' C:\DefenderTemp\_DefenderAVBackup.reg}
    1. Remove Defender policies that may be forcing it off. This is a registry change. Incorrect changes can affect security settings. In an elevated PowerShell session, run:
    Remove-Item -Path 'HKLM:\SOFTWARE\Policies\Microsoft\Windows Defender' -Force
    1. Run Microsoft Update after the reset. The documented resolution includes updating after the platform reset.
    2. If scans still fail near the end, check whether the issue is tied to update or engine errors. Documented guidance for repeated Defender scan errors is to:
    • run Windows Update
    • try installing the latest protection updates manually
    • submit feedback through Feedback Hub if the issue continues
    1. If the service still shows as stopped in Windows Security but appears running in services.msc, check for policy or compatibility causes. Generate a Group Policy report from an elevated Command Prompt:
    GPresult.exe /h gpresult.html

    Then review gpresult.html for:

    • Turn off Microsoft Defender Antivirus = Enabled
    • DisableAntiSpyware under HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender

    If those are present, Defender may be disabled by policy rather than failing normally.

    1. If the service cannot be started cleanly from Services, try the documented service check flow:
    • open services.msc
    • select Windows Defender Antivirus Service
    • confirm Startup Type is Automatic
    • use Action > Start
    • if Start is unavailable, use Stop, wait for it to stop, then use Start again

    If an error appears during that process, collect the exact error text.

    AI-generated content may be incorrect. Read our transparency notes for more information.

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