I've seen a few other very similar posts but still can't find a cure.
I have WinXPsp2 p.c.'s with 4.90sp2 clients that may log in fine during
the morning and then later in the day go to a mapped drive and they're
gone. If I watch the login messages, they authenticate to server fine
but never map the drive. Odd thing is after a couple reboots it
finally comes back. What's odd is the it's sporadic and happens to
different users daily.

Server is NW6sp5.