One of the new default Vista security policy settings needs to be adjusted
For Vista Ultimate:
Start,Run secpol.msc [enter]
Click on Local Policies then Security Options
Navigate to
Network Security: LAN Manager authentication level
double-click to display Properties.
The default Windows Vista policy is NTVLM2 responses only.
Use the drop-down arrow to change this to
LM and NTLM – use NTLMV2 session security if negotiated
For Vista Home Premium:
Open a cmd prompt "as administrator" and ack the prompt
Type regedit [enter]
Navigate to
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
If it doesn't already exist, create a DWORD value named LmCompatibilityLevel
Set the value to 1 and reboot