nas not accessible from windows when user is assigned

[beng]

Multiple connection to a server or shared resource by the same user, using more than one user name, are not allowed. Disconnect all previous connections to the server or shared resource and try again.

Yep, I think this is where you are coming unstuck.

(This is not a verified statement, just off the top of my head)
When Windows authenticates to a network share it tries your logged on credentials(ie windows username etc), then tries the guest credentials.
If the guest works, you have an "authenticated session"(even though it is a guest) with the CIFS/SMB server.
If you then try and access another share that requires different authentication, it fails and prompts for a user/pass. But the kicker is that Windows will not then "renegotiate", and you get the Multiple sessions error.
As I mentioned, the fix I use is to create a batch that deletes the session, then creates one with the right user/pass combo and you should be fine.

Rgds Ben

[To-M]

I believe Ben has figured this one out