When I setup DFS file shares in Windows 2003 server. The vista computers can not access the shares. They can map the shares. The shares show up in "My Computer" and "Explore" You can even see the files on the shares. But when you start to copy large files to/from the DFS shares they just disappear. If you map to the IP addresses everything works fine. But the DFS shares do not work reliably. This is the RTM version of vista with Windows 2003 SP1.