Microsoft Defender Antivirus Service (WinDefend) Defaults in Windows 11

Helps protect users from malware and other potentially unwanted software.

Default Settings

Startup type: Automatic
Display name:Microsoft Defender Antivirus Service
Service name:WinDefend
Service type:own
Error control:normal
Object:LocalSystem
Path:%ProgramFiles%\Windows Defender\MsMpEng.exe
Registry key:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WinDefend
Privileges:
  • SeImpersonatePrivilege
  • SeBackupPrivilege
  • SeRestorePrivilege
  • SeDebugPrivilege
  • SeChangeNotifyPrivilege
  • SeLoadDriverPrivilege
  • SeSecurityPrivilege
  • SeShutdownPrivilege
  • SeIncreaseQuotaPrivilege
  • SeAssignPrimaryTokenPrivilege
  • SeTcbPrivilege
  • SeIncreaseBasePriorityPrivilege
  • SeSystemEnvironmentPrivilege
  • SeTakeOwnershipPrivilege

Default Behavior

Microsoft Defender Antivirus Service is a Win32 service. In Windows 11 it starts automatically during the operating system startup. Then the Microsoft Defender Antivirus Service logs on as LocalSystem and running in its own process of MsMpEng.exe. If Microsoft Defender Antivirus Service fails to start, the failure details will be recorded into Event Log. Then Windows 11 should boot up and notify the user about the WinDefend service startup failure.

Dependencies

Microsoft Defender Antivirus Service cannot be started, if the Remote Procedure Call (RPC) service won't start.

Restore Default Startup Configuration of Microsoft Defender Antivirus Service

Before you begin doing this, make sure that all the services on which Microsoft Defender Antivirus Service depends are configured by default and function properly. See the list of dependencies above.

1. Run the Command Prompt as an administrator.

2. Copy the commands below, paste them into the command window and press ENTER:

sc config WinDefend start= auto
sc start WinDefend

3. Close the command window and restart the computer.

The WinDefend service is using the MsMpEng.exe file that is located in the %ProgramFiles%\Windows Defender directory. If the file is removed or corrupted, read this article to restore its original version from Windows 11 installation media.