trouble connecting vista and OS X

[Harp]

I'm trying to enable file/printer sharing between my macbook pro running 10.4.10 and my wife's PC running Vista.

The two computers are connected to the same network and I've put them in the same workgroup, turned on windows sharing and all that. The PC recognizes my mac but won't let me sign on to it, saying that my login information is incorrect when I know damn well it isn't.
At this point the Mac Help suggests changing my password in the accounts pane which I've done a few times to no avail.

Does anyone have any ideas what I'm doing wrong?
This is the first time that i've attempted this so I'll try not to be embarrassed if I've missed a step.

Thanks!

[kenny]

This is a somewhat well-known issue in the Linux crowd 'cos it breaks there for the same reason. Thanks Microsoft!!

The short version of the answer is that, with Vista, the NTLM negotiation is set a bit more strictly than pretty much anyone else in the industry, for all the good that'll do 'em. If you Google for "Vista ntlmv2 samba", you'll turn up all the ugly details. Anyway, the fix is to use the policy editor to relax that a bit. I found, doing the same Google search, someone else had typed up the steps that I've done too many times to remember to fix this... thing:

Click "Start -> Run." Then, type in the Run field: "secpol.msc." That will bring you to Vista's security policy system. Once there, use "Go to: Local Policies > Security Options" and then find "Network Security: LAN Manager" authentication level. Once there, change the Setting from "Send NTLMv2 response only" to "Send LM & NTLM -- use NTLMv2 session security if negotiated."

This fix is immediate - no reboot or logout/in needed. But, you might end up doing so anyway because of the sticky nature of ntlm-style sessions. I could explain, but it's not really that interesting. It is Vista, after all...