Skip to main content

Disable insecure "LM & NTLM" protocols

Apply Now
Works with Windows 10 and 11Works with Windows Vista, XP, 7, 8, 10, 11, and Windows Server 2008 or newer.
  • Single actionThis page belongs to a script, containing basic changes to achieve a task.
  • Windows onlyThis script improves your privacy on Windows
  • Impact: MinimumSystem Functionality Loss Risk: Low
    This action improves privacy with minimal impact when you run the recommended script.
  • Batch (batchfile)These changes use Windows system commands to update your settings.
  • Fully reversible

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

    The restore/revert methods provided here can help you fix issues.

Overview​

This script improves security by setting the LanMan authentication level to send NTLMv2 responses only, refusing LM and NTLM 1 2, which are older and less secure methods 1 3.

While Kerberos v5 is the default authentication protocol for domain accounts, NTLM is still used for compatibility with older systems and for authenticating logons to standalone computers 1.

The script modifies the HKLM\System\CurrentControlSet\Control\Lsa!LmCompatibilityLevel registry key to enforce this security measure 1 2.

Caution

This may cause compatibility issues with older devices or software.

Safe for General Use
All actions in this script is recommended for all users. This is recommended for all users to improve without any noticeable impact on the system functionality.
Sources
PrivacyLearn.com maintains strict sourcing standards for accuracy, integrity and up-to-date content. Our content relies on authoritative sources including vendor documentation, industry standards, and verified research. Learn more about our verification process and quality standards in our editorial standards page.

Apply Now​

Choose one of three ways to apply:

Download script​

Download and run the script directly
  • No app needed
  • Offline usage
  • Easy-to-apply
  • Free
  • Open-source
Help

How to apply or restore "Disable insecure "LM & NTLM" protocols" using script​

  • ≈ 2 min to complete
  • Tools: Web Browser
  • Difficulty: Simple
  • ≈ 5 instructions
  1. 1

    Download

    Download the script file by clicking on the   Apply protection  button above.
    Use   Undo protection button above to restore changes.
  2. 2

    Keep the file

    If warned by your browser, keep the file.
  3. 3

    Open

    Open the downloaded file.
  4. 4

    Exit

    Once it's done, press any key to exit the window.
  5. 5

    Restart

    Restart your computer for all changes to take effect.

Apply with privacy.sexy​

Guided, automated application with safety checks
  • Recommended for most users
  • Includes safety checks
  • Free
  • Open-source
  • Popular
  • Offline/Online usage
Open privacy.sexy
Help

How to apply or restore "Disable insecure "LM & NTLM" protocols" using privacy.sexy​

  • ≈ 3 min to complete
  • Tools: privacy.sexy
  • Difficulty: Simple
  • ≈ 4 instructions
privacy.sexy is free and open-source application that lets securely apply this action easily with more advanced options.
  1. 1

    Open or download

    Open or download the desktop application
  2. 2

    Choose script

    1. Search for the script name: Disable insecure "LM & NTLM" protocols
    2. Check the script by clicking on the checkbox.
  3. 3

    Run

    Click on ▶️ Run button at the bottom of the page.

    This button only appears on desktop version (recommended). On browser, use 💾 Save button.

Run commands​

Copy and run commands manually Requires technical knowledge
Apply changes
:: Set the registry value: "HKLM\SYSTEM\CurrentControlSet\Control\Lsa!LmCompatibilityLevel"
PowerShell -ExecutionPolicy Unrestricted -Command "$registryPath = 'HKLM\SYSTEM\CurrentControlSet\Control\Lsa'; $data =  '5'; reg add 'HKLM\SYSTEM\CurrentControlSet\Control\Lsa' /v 'LmCompatibilityLevel' /t 'REG_DWORD' /d "^""$data"^"" /f"
Help

How to apply or restore "Disable insecure "LM & NTLM" protocols" using commands​

  • ≈ 2 min to complete
  • Tools: Command Prompt
  • Difficulty: Medium
  • ≈ 3 instructions
 View step-by-step guide with screenshots
  1. 1

    Open Command Prompt

    Open Command Prompt as Administrator.
  2. 2

    Copy code

    Copy the code:
    Copy Apply Code Copy Revert Code
  3. 3

    Paste & run

    Paste the commands into Command Prompt and press Enter to run.

    Some changes require a system restart to take effect

Similar Guides​

Wider Goal​

Guides below includes this guide to achieve a wider goal.See other more general settings that includes this one as one of its actions.
These plans combine multiple privacy settings, including this one, for stronger protection.
This category focuses on enhancing user privacy by disabling legacy and insecure communication protocols. It targets protocols that expose users to secur...

— Disable insecure protocols

Same Goal​

Other guides in Disable insecure protocols See settings that are in the same category as this guide.
Using other actions in the same category may help you achieve your goal better.
See all 7 guides

About the Creators​

These people have authored this documentation and written its scripts:

  • Avatar of undergroundwires. The creator of PrivacyLearn and privacy.sexy. Black and white portrait showing a person wearing a polka dot tie and suit jacket, reflecting the professional expertise behind the privacy protection tools.
    • Certified security professional
    • 7+ years experience securing banks
    • Open-source developer since 2005
    • EU advisor, Public Speaker, Moderator
    • Hundreds across the globe
    • Testers, reviewers, developers
    • Companies, military agencies
    • Community since 2017
About Us

Reviewed By​

This guide has undergone comprehensive auditing and peer review:

  • Expert review by undergroundwires​

    • Verified technical accuracy and editorial standards
    • Assessed system impact and user privacy risks
    • Audited and verified using automated security tests

  • Public review by large community​

    • Privacy enthusiasts and professionals peer-reviewed
    • Millions of end-users tested across different environments
    • Audited and verified using third-party security software

History​

We continually monitor our guides, their impact and other potential privacy options. We update our guides when new information becomes available. On every update, we publicly store who made the change, what has been changed, why the change was made and when the change was made.

Review Change History Our Change Process