Veja este post (por que vale a pena) por komickaze @ link :
I had a similar problem when trying to connect Windows 7 Home Premium and Windows 7 Ultimate to a Mac OS 10.3.9 Server. I made the following change with the Local Security Policy on Ultimate and tested it successfully while watching the registry for changes. I found the following REG_DWORD values were changed:
HKLM\System\CurrentControlSet\Control\Lsa\LmCompatibilityLevel HKLM\System\ControlSet001\Control\Lsa\LmCompatibilityLevel
After further testing, I found these to be the values and coresponding settings:
0) Send LM & NTLM responses
1) Send LM & NTLM - use NTLMv2 session security if negotiated
2) Send NTLM response only
3) Send NTLMv2 response only
4) Send NTLMv2 response only. Refuse LM
5) Send NTLMv2 response only. Refuse LM & NTLM
I created the LmCompatibilityLevel setting on my Home Premium machine with a value of 1 (http://www.builderau.com.au/blogs/codemonkeybusiness/viewblogpost.htm?p=339270746) and was finally able to connect to the 10.3.9 Server.
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