It may be an ancient thread, but it really is valuable if you are tearing your hair out. I have only a little left, so... I just upgraded to Vista Ult64 and had less than stellar results with the connections. My issue is that I needed to connect my mac to my local workgroup. (generally the opposite of what is discussed here. I also use parallels with both XP and Vista Ult available.

However, connections to the Vista machine/workgroup was spotty at best. After looking through this list, two comments stood out: DON'T use dashes in your Vista PC name! My pc was named Mediacenter-PC. I changed it to MediacenterPC. AND Use the Administrative tools -> Local Security Policies -> Local Policies,

Then scroll down the list until you get to Microsoft Network Server: entries. and change these: Amount of idle time required before suspending session: 99999 Disconnect clients when logon hours expire: Disabled

Network Security entries. There are a couple things there that have changed in Vista: Force Logoff when logon hours expire: Set this to Disabled LAN Manager Authentication Level: Set this to Send LM & NTLM - use NTLMv2 session security if negotiated

I did these, rebooted, and attempted to access my vista machine from my mac. I used finder then command-K The entry is SMB://vistamachinename

It popped right up and asked me for the user/password for the vista machine. Even if you don't have your drives shared, you can add /C$ or /D$ in the SMB line to get directly to your drives.

Hope this helps - Saved my bacon...