It looks like Microsoft has identified a problem with Ntlanman.dll and created a hotfix. It looks like they have rolled the update into Windows 2003 SP2 and may be slated to include the update in XP SP3.
To recreate the problem:
- Apply the group policy (gpupdate /force) and logout
- Login as user with My Documents redirected
- Log out and in again to see no login time penalty
- Force the application of group policy (gpupdate /force) and logout
- or wait a day or two for the policy to refresh on its own
You may experience a 20-second delay when you try to access a redirected folder by logging on to a Windows Server 2003 Service Pack 1-based computer or to a Windows XP Service Pack 2-based computer