Windows 7 cannot access NAS or Samba server

                  By default, Windows 7 does not have proper access to shared folders on NAS or Samba servers. The reason is that starting from Vista, Microsoft only uses the NTLM v2 protocol authentication response message by default, while the current NAS system and Samba only support LM or NTLM. Workaround: Modify the local security policy or modify the registry directly to modify the local security policy
1) Run secpol.msc

2) Modify the "Network security: LAN Manager authentication level" value to "Send LM&NTLM – use NTLMv2 session security if negotiated”

Modify the registry
Modify the value of LmCompatibilityLevel under HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Control\\Lsa to 1.