I just changed out a set of small residential hubs for a switch in a small office. The systems was setup 10 years ago, and I found at the change that the person who set it up had all internet traffic passing through the server, so I changed that to a flat topology. Server and workstations are on one router. After the change things seemed great. After the machines slept some lost drive mappings. Reattaching seemed to solve, but more lost mappings the next day. Now, all but 2 machines are connected and good. 2 will not reconnect the drives, claiming the username or password to connect is wrong, but both have permissions, and sign into the domain at login. DCDiag kicks back an LDAP error, and trying to map the drives manually kicks a username or password error, no matter what username or password is used.