Microsoft deprecates Windows NTLM authentication protocol

Microsoft is deprecating NTLM across Windows and Windows Server due to long-known security weaknesses and abuse in attacks like NTLM relay and pass-the-hash, urging migration to Kerberos or Negotiate with auditing to identify NTLM usage and generally minimal code changes via SSPI. NTLM will continue to function in upcoming Windows releases with Negotiate fallback for compatibility, but administrators are encouraged to plan transitions and leverage Microsoft’s Kerberos troubleshooting guidance.