Would you like to learn how to use a group policy to disable NTLM version 1 on Windows? In this tutorial, we will show you how to create a group policy to force the utilization of NTLM version 2 on Windows.
• Windows 2012 R2
• Windows 2016
• Windows 2019
• Windows 2022
• Windows 10
• Windows 11
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Tutorial GPO – Disable NTLM version 1
On the domain controller, open the group policy management tool.
Create a new group policy.
Enter a name for the new group policy.
In our example, the new GPO was named: MY-GPO.
On the Group Policy Management screen, expand the folder named Group Policy Objects.
Right-click your new Group Policy Object and select the Edit option.
On the group policy editor screen, expand the Computer configuration folder and locate the following item.
Access the folder named Security options.
Access the item named Network Security: LAN Manager authentication level.
Select the option to send only NTLMv2 response.
Desktops and member servers will accept only NTLM version 2.
Domain controllers will still accept NTLMv1.
To configure domain controllers to accept only NTLM version 2, select the option named Send NTLMv2 response only. Refuse LM & NTLM.
To save the group policy configuration, you need to close the Group Policy editor.
Congratulations! You have finished the GPO creation.
Tutorial GPO – Disable NTLMv1
On the Group policy management screen, you need to right-click the Organizational Unit desired and select the option to link an existent GPO.
In our example, we are going to link the group policy named MY-GPO to the root of the domain.
After applying the GPO you need to wait for 10 or 20 minutes.
During this time the GPO will be replicated to other domain controllers.
In our example, we disabled the NTLMv1 authentication using a GPO.
