The following operating systems include full support for DFS Namespaces, including support for client failback to the preferred folder target:

These hotfixes are described in article 898900 in the Microsoft Knowledge Base (http://go.microsoft.com/fwlink/?LinkId=53202).

Users who are running the following operating systems can access namespaces, but if a folder target becomes unavailable and then later comes back online, the computer will not fail back (return) to the preferred folder target.