Making Windows Vista PC's compatible with Buffalo NAS products

Open the control panel, make sure you're using the classic view, and double-click on "Administrative Tools".  There is an item "Local Security Policy"- open it.

Alternative click the start button and type secpol.msc in the search function.

Browse to [Local Policies] - [Security Options]. Now look for the entry "Network Security: LAN Manager authentication level" and open it.
Click on the menu and select "Send LM & NTLM - use NTLMv2 session security if negotiated". Apply the settings.

On Vista Home or Home Premium - there is only the way of changing the registry entry.

Open the registry editor. (Start- type regedit)

[HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlLsa]

"LmCompatibilityLevel"

Set the value to 2 and if you have further problems to 1. Restart the PC after changing the registry. Otherwise all changes you made are not valid.

Please note that NTLM has security problems.