Hi Doran,
first thing to try would be check, if there are more current updates for the network card on the server and the clients and apply those.
Second: Is there anything running on the server, which is causing a high load on network or disk subsystem at that time (i.e. Volume Shadow Copies or DFS-R replication)? If so try to schedule them not to run during prime business hours.
Is there anything visible in the event logs of the server? Might also be interesting to use resource monitor on the server (we had a Dell Server acting in a very similar way, even locally on the server the drive with the shared folder rendered
unusable and did not show the disk fill bar anymore) and the only solution was finally to disable DFS-R for the data shares during daytime).
Are network drives excluded from scans with virus scanner?
Would a connection between two client PCs remain stable?
Best greetings from Germany
Olaf
