Many NAS devices are being outdated by newer operating systems. When Microsoft's Windows Vista began showing up in corporations, networking problems and woes began to show up against some network area storage devices.
NTLM is a Microsoft authentication protocol that is used with the SMB (Server Message Block that operates at the application level protocol) protocol.
On a Windows Vista Computer
select Administrative Tools->Local Security Policy.
Select Local Policies->Security Options->Network security->LAN Manager authentication level.
Select this and use the drop down to change it to:
Use the setting “Send LM & NTLM - use NTLM v.2 if negotiated”
Losing connectivity to these devices can cause a security issue.