ARCHIVED: In Windows XP Home, how do I enable NTLMv2?

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Important: As of April 8, 2014, Microsoft no longer supports Windows XP with security updates. To ensure the highest security standards, the UITS Support Center no longer registers Windows XP devices to the IU network. UITS strongly recommends that you look into the options for replacing or upgrading your Windows XP computers for full compatibility with IU systems. See About end of life for Windows 8.0, 7, Vista, and XP.

Note: By following these instructions, you will change your Windows client to use only NTLMv2 authentication and refuse everything else. In changing to this highest level of security, you may have difficulty connecting to other Windows computers that have not had the equivalent change made.

Warning:
This contains instructions for editing the registry. If you make any error while editing the registry, you can potentially cause Windows to fail or be unable to boot, requiring you to reinstall Windows. Edit the registry at your own risk. Always back up the registry before making any changes. If you do not feel comfortable editing the registry, do not attempt these instructions. Instead, seek the help of a computing support provider.

To enable NTLMv2 on a Windows XP Home system, you need to make a change to the Windows registry. To do so:

  1. From the Start menu, select Run....
  2. Enter regedt32. Click OK.
  3. Double-click HKEY_LOCAL_MACHINE, then SYSTEM, CurrentControlSet, Control, and finally LSA.
  4. In the right pane, double-click the LMCompatibilityLevel value.
  5. In the "Data" field of the DWORD Editor window, enter 5. Click OK.
  6. In the Registry menu, select Exit.
  7. Restart your system for the registry changes to take effect.

This is document atcm in the Knowledge Base.
Last modified on 2021-09-07 17:10:16.