There are certain clients on our domain that  lose connection to our file
server and domain controller at certain times of the day.  All clients end up
losing connection to all their mapped drives.  To resolve this, the clients
usually has to log off and log back on.  Then the connections are stable for
a couple of hours.  Please help...this is a pain in the arse!

Hi,
on the related servers you can try the following command:
net config server /autodisconnect:-1
This will disable the automatic disconnect of connected ressources after a
certain idle time (which saves bandwidth).

But since this are only "certain" clients I am almost sure that this will
not help that much.
So you need to provide more information:
Which operating systems are involved on server and client?
Which entries are there in the event log on client and server pointing to
problems?
Do all the clients and the server use the same network protocoll and have
only one single NIC?
Are the affected clients connected to the same switch or hub, which may
cause problems?
Best greetings from Germany
Olaf.

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