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Disable Defender Antivirus service automatic launch

Overview​

About this script

This script improves your privacy on Windows.

These changes use Windows system commands to update your settings.

This script prevents the Defender Antivirus service from starting automatically.

By default, Windows may automatically start the Defender Antivirus service (also called the Antimalware Service 1) under specific conditions 2 3. This script allows you to control when the service runs.

This script enhances privacy by preventing unexpected Defender Antivirus scans and data collection. It may improve system performance by stopping the service from using system resources without your permission.

However, it may reduce security by stopping Defender Antivirus from automatically activating against potential threats.

Caution

Disabling automatic launch may leave your system vulnerable if you forget to manually activate Defender Antivirus when needed.

Technical Details​

This script sets the ServiceStartStates registry value to 0 in the Defender Antivirus registry key:

  • 0 indicates the service is turned off and won't start automatically; 1 means it will 4.
  • When a third-party antivirus is installed, Windows typically sets this value to 0 2.
  • Default values can vary; tests show that it is missing in fresh installations of both Windows 11 and Windows 10 5.
  • The MpSvc.dll 6 and MpClient.dll 7 files read this registry value to manage Defender Antivirus operations.

This script uses Batch (batchfile) scripting language.

Not Advised

This script should only be used by advanced users. This script is not recommended for daily use as it breaks important functionality. Do not run it without having backups and system snapshots.

Implementation Details

  • Language: batch

  • Required Privileges: Administrator rights

  • Compatibility: Windows only

  • Reversibility: Can be undone using provided revert script

Explore Categories​

This action belongs to Disable Defender Antivirus service category. This category disables the Defender Antivirus service and its related components. This service is also referred to as Microsoft Defender Antivirus Service and Windows Defender Service. It is a core component of Microsoft Defender Antivirus, essential for its operation. Using these... Read more on category page ▶

Apply now​

Choose one of three ways to apply:

  1. Automatically via privacy.sexy: The easiest and safest option.
  2. Manually by downloading: Requires downloading a file.
  3. Manually by copying: Advanced flexibility.

Alternative 1. Apply with Privacy.sexy​

privacy.sexy is free and open-source application that lets securely apply this action easily.

Open privacy.sexy

You can fully restore this action (revert back to the original behavior) using the application.

privacy.sexy instructions
  1. Open or download the desktop application
  2. Search for the script name: Disable Defender Antivirus service automatic launch.
  3. Check the script by clicking on the checkbox.
  4. Click on Run button at the bottom of the page.

Alternative 2. Download​

Irreversible Changes

This script is irreversible, meaning there is no straightforward method to restore changes once applied. Exercise caution before running, restoring it may not be possible.

  1. Download the script file by clicking on the button below:

    Download script

  2. Run the script file by clicking on it.

Download revert script​

This file restores your system to its original state, before this script is applied.

Download restore script

Alternative 3. Copy​

This is for advanced users. Consider automatically applying or downloading the script for simpler way.

  1. Open Command Prompt as administrator.
HELP: Step-by-step guide

  1. Click on Start menu

  2. Type cmd

  3. Right click on Command Prompt select Run as administrator

  4. Click on Yes to run Command Prompt

Animation showing how to open terminal as administrator on Windows 11

  1. Copy the following code:
Code to apply changes
:: Set the registry value: "HKLM\SOFTWARE\Microsoft\Windows Defender!ServiceStartStates"
PowerShell -ExecutionPolicy Unrestricted -Command "function Invoke-AsTrustedInstaller($Script) { $principalSid = [System.Security.Principal.SecurityIdentifier]::new('S-1-5-80-956008885-3418522649-1831038044-1853292631-2271478464'); $principalName = $principalSid.Translate([System.Security.Principal.NTAccount]); $streamFile = New-TemporaryFile; $scriptFile = New-TemporaryFile; try { $scriptFile = Rename-Item -LiteralPath $scriptFile -NewName ($scriptFile.BaseName + '.ps1') -Force -PassThru; $Script | Out-File $scriptFile -Encoding UTF8; $taskName = "^""privacy$([char]0x002E)sexy invoke"^""; schtasks.exe /delete /tn $taskName /f 2>&1 | Out-Null; $executionCommand = "^""powershell.exe -ExecutionPolicy Bypass -File '$scriptFile' *>&1 | Out-File -FilePath '$streamFile' -Encoding UTF8"^""; $action = New-ScheduledTaskAction -Execute 'powershell.exe' -Argument "^""-ExecutionPolicy Bypass -Command `"^""$executionCommand`"^"""^""; $settings = New-ScheduledTaskSettingsSet -AllowStartIfOnBatteries -DontStopIfGoingOnBatteries; Register-ScheduledTask -TaskName $taskName -Action $action -Settings $settings -Force -ErrorAction Stop | Out-Null; try { ($scheduleService = New-Object -ComObject Schedule.Service).Connect(); $scheduleService.GetFolder('\').GetTask($taskName).RunEx($null, 0, 0, $principalName) | Out-Null; $timeout = (Get-Date).AddMinutes(5); Write-Host "^""Running as $principalName"^""; while ((Get-ScheduledTaskInfo $taskName).LastTaskResult -eq 267009) { Start-Sleep -Milliseconds 200; if ((Get-Date) -gt $timeout) { Write-Warning 'Skipping: Timeout'; break; }; }; if (($result = (Get-ScheduledTaskInfo $taskName).LastTaskResult) -ne 0) { Write-Error "^""Failed, due to exit code: $result."^""; } } finally { schtasks.exe /delete /tn $taskName /f | Out-Null; }; Get-Content $streamFile } finally { Remove-Item $streamFile, $scriptFile; }; }; $cmd = '$registryPath = ''HKLM\SOFTWARE\Microsoft\Windows Defender'''+"^""`r`n"^""+'$data = ''0'''+"^""`r`n"^""+''+"^""`r`n"^""+'reg add ''HKLM\SOFTWARE\Microsoft\Windows Defender'' `'+"^""`r`n"^""+'    /v ''ServiceStartStates'' `'+"^""`r`n"^""+'    /t ''REG_DWORD'' `'+"^""`r`n"^""+'    /d "^""$data"^"" `'+"^""`r`n"^""+'    /f'; Invoke-AsTrustedInstaller $cmd"
  1. Right click on command prompt to paste it.
  2. Press Enter to apply remaining code.

Copy restore code​

Copy and run the following code to restore changes:

Revert code
:: Delete the registry value "HKLM\SOFTWARE\Microsoft\Windows Defender!ServiceStartStates"
PowerShell -ExecutionPolicy Unrestricted -Command "function Invoke-AsTrustedInstaller($Script) { $principalSid = [System.Security.Principal.SecurityIdentifier]::new('S-1-5-80-956008885-3418522649-1831038044-1853292631-2271478464'); $principalName = $principalSid.Translate([System.Security.Principal.NTAccount]); $streamFile = New-TemporaryFile; $scriptFile = New-TemporaryFile; try { $scriptFile = Rename-Item -LiteralPath $scriptFile -NewName ($scriptFile.BaseName + '.ps1') -Force -PassThru; $Script | Out-File $scriptFile -Encoding UTF8; $taskName = "^""privacy$([char]0x002E)sexy invoke"^""; schtasks.exe /delete /tn $taskName /f 2>&1 | Out-Null; $executionCommand = "^""powershell.exe -ExecutionPolicy Bypass -File '$scriptFile' *>&1 | Out-File -FilePath '$streamFile' -Encoding UTF8"^""; $action = New-ScheduledTaskAction -Execute 'powershell.exe' -Argument "^""-ExecutionPolicy Bypass -Command `"^""$executionCommand`"^"""^""; $settings = New-ScheduledTaskSettingsSet -AllowStartIfOnBatteries -DontStopIfGoingOnBatteries; Register-ScheduledTask -TaskName $taskName -Action $action -Settings $settings -Force -ErrorAction Stop | Out-Null; try { ($scheduleService = New-Object -ComObject Schedule.Service).Connect(); $scheduleService.GetFolder('\').GetTask($taskName).RunEx($null, 0, 0, $principalName) | Out-Null; $timeout = (Get-Date).AddMinutes(5); Write-Host "^""Running as $principalName"^""; while ((Get-ScheduledTaskInfo $taskName).LastTaskResult -eq 267009) { Start-Sleep -Milliseconds 200; if ((Get-Date) -gt $timeout) { Write-Warning 'Skipping: Timeout'; break; }; }; if (($result = (Get-ScheduledTaskInfo $taskName).LastTaskResult) -ne 0) { Write-Error "^""Failed, due to exit code: $result."^""; } } finally { schtasks.exe /delete /tn $taskName /f | Out-Null; }; Get-Content $streamFile } finally { Remove-Item $streamFile, $scriptFile; }; }; $cmd = 'reg delete ''HKLM\SOFTWARE\Microsoft\Windows Defender'' `'+"^""`r`n"^""+'        /v ''ServiceStartStates'' `'+"^""`r`n"^""+'        /f 2>$null'; Invoke-AsTrustedInstaller $cmd"

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