Troubleshoot Microsoft Defender Antivirus service startup problems

In the following screenshot, Virus & threat protection displays a red cross, where it says Threat service has stopped. Restart it now.

Within Security Providers, you can see the following result.

Microsoft Defender Antivirus is turned off.

The following screenshot displays the message: Threat service has stopped. Restart it now.

The following screenshot displays the message: Unexpected error. Sorry, we ran into a problem. Please try again.

Select Close.

Events

The Windows Defender – Operational event log might display the following events:

Event 5007

The configuration of Microsoft Defender Antivirus changed. If you expected this event, review the settings, as it might be the result of malware.

Old value	New value
HKLM\SOFTWARE\Microsoft\Windows Defender\Diagnostics\RolledbackPlatformHealthData = <OVERALL>:<BAD>, <AGE>:<36>, <DIRTY_SHUTDOWNS>:<22>	Default\Diagnostics\RolledbackPlatformHealthData = 0
Default\ServiceStartStates = 0x0	HKLM\SOFTWARE\Microsoft\Windows Defender\ServiceStartStates = 0x1
HKLM\SOFTWARE\Microsoft\Windows Defender\ServiceStartStates = 0x1	Default\ServiceStartStates = 0x0
Default\ProductAppDataPath = C:\ProgramData\Microsoft\Windows Defender	HKLM\SOFTWARE\Microsoft\Windows Defender\ProductAppDataPath = C:\ProgramData\Microsft\Windows Defender
Default\IsServiceRunning = 0x0	HKLM\SOFTWARE\Microsoft\Windows Defender\IsServiceRunning = 0x1
Default\ProductAppDataPath = C:\ProgramData\Microsoft\Windows Defender	HKLM\SOFTWARE\Microsoft\Windows Defender\ProductAppDataPath = C:\ProgramData\Microsoft\Windows Defender
Default\IsServiceRunning = 0x0	HKLM\SOFTWARE\Microsoft\Windows Defender\IsServiceRunning = 0x1

Event 5001

Microsoft Defender Antivirus Real-time Protection scanning for malware and other potentially unwanted software was disabled.

Resolution

To resolve the issue, do the following steps:

1. Check the services and filter drivers for Microsoft Defender Antivirus.

   Run the following command in an elevated PowerShell window (a PowerShell window you opened by selecting Run as administrator):

   Get-Service WinDefend, WdBoot, WdFilter, WdNisSvc, WdNisDrv, SecurityHealthService, wscsvc | Format-Table -Auto DisplayName, Name, StartType, Status
   

   Display Name	Name	StartType	Status	Comments
   Windows Security Service	SecurityHealthService	Manual	Running
   Microsoft Defender Antivirus Boot Driver	WdBoot	Boot	Stopped	It's normal to be stopped after boot.
   Microsoft Defender Antivirus Mini-Filter Driver	WdFilter	Boot	Running	If stopped, check steps 3, 6, 7.
   Microsoft Defender Antivirus Network Inspection System Driver	WdNisDrv	Manual	Running	If stopped, check steps 3, 6, 7.
   Microsoft Defender Antivirus Network Inspection Service	WdNisSvc	Manual	Running	If stopped, check steps 3, 6, 7.
   Microsoft Defender Antivirus Service	WinDefend	Automatic	Running	If stopped, check steps 3, 6, 7.
   wscsvc	Security Center	Automatic	Running

2. Download and run the Microsoft Safety Scanner to rule out any malware.

3. If you're using Microsoft Defender Antivirus as your primary antivirus, make sure to uninstall non-Microsoft antivirus software.

4. Remove the Security Intelligence and engine:

   1. Open an elevated Command Prompt (a Command Prompt window you opened by selecting Run as administrator). For example:

      1. Open the Start menu, and then type cmd.
      2. Right-click on the Command Prompt result, and then select Run as administrator.

   2. In the elevated Command Prompt, run the following commands.

      Tip

      The first command changes the directory to the latest version of <antimalware platform version> in %ProgramData%\Microsoft\Windows Defender\Platform\<antimalware platform version>. If that path doesn't exist, it goes to %ProgramFiles%\Microsoft Defender.

      (set "_done=" & if exist "%ProgramData%\Microsoft\Windows Defender\Platform\" (for /f "delims=" %d in ('dir "%ProgramData%\Microsoft\Windows Defender\Platform" /ad /b /o:-n 2^>nul') do if not defined _done (cd /d "%ProgramData%\Microsoft\Windows Defender\Platform\%d" & set _done=1)) else (cd /d "%ProgramFiles%\Windows Defender")) >nul 2>&1
      
      MpCmdRun.exe -RemoveDefinitions -All
      

   For more information, see Manage the sources for Microsoft Defender Antivirus protection updates.

5. Backup Microsoft Defender Antivirus policies.

   1. Open an elevated PowerShell session (a PowerShell window you opened by selecting Run as administrator). For example:

      1. Open the Start menu, and then type powershell.
      2. Right-click on the PowerShell 7 (x64) or Windows PowerShell result, and then select Run as administrator.

   2. In the elevated PowerShell session, run the following command:

   New-Item -Path "C:\DefenderTemp" -ItemType Directory; Invoke-Command {reg export 'HKLM\SOFTWARE\Policies\Microsoft\Windows Defender' C:\DefenderTemp\_DefenderAVBackup.reg}
   

6. "Reset" Microsoft Defender Antivirus. Microsoft Defender Antivirus is built into Windows 10 and Windows 11, so you can't remove it.

   Run the following commands in an elevated Windows Command Prompt:

   • Windows 10 or later:

     1.  

        DISM /Online /Cleanup-Image /RestoreHealth
        

        or

         DISM /Online /Cleanup-Image /RestoreHealth /Source:<SourcePath> /LimitAccess
        

     2.  

        sfc /scannow
        

7. Delete any policies that are set for Microsoft Defender Antivirus.

   Run the following command in an elevated PowerShell session:

   Remove-Item -Path 'HKLM:\SOFTWARE\Policies\Microsoft\Windows Defender' -Force
   

   For more information, see: Troubleshoot Microsoft Defender Antivirus settings.

8. Update Security Intelligence.

   Run the following commands in an elevated Command Prompt:

   (set "_done=" & if exist "%ProgramData%\Microsoft\Windows Defender\Platform\" (for /f "delims=" %d in ('dir "%ProgramData%\Microsoft\Windows Defender\Platform" /ad /b /o:-n 2^>nul') do if not defined _done (cd /d "%ProgramData%\Microsoft\Windows Defender\Platform\%d" & set _done=1)) else (cd /d "%ProgramFiles%\Windows Defender")) >nul 2>&1
   
   MpCmdRun.exe -SignatureUpdate -MMPC
   

9. Verify Tamper Protection is enabled.

   

10. Run Microsoft Update.