Cliff notes- Enterprise Edition installed on SBS2003 network. Clients all running XP Pro. Server running AMON; DMON; EMON; XMON. No IMON installed on the server. Mirror set up for HTTP. All this works fine. Every hour or so, when a client saves a file (CAD dwg files, XLS, DOC) it will cause the server to almost lock up- It is the System process hanging the server. This will sit this way for 30-60 seconds. During that time, server CPU usage goes up to about 25-30%. The client workstations that are trying to save are hung as well until this clears out. This condition did not exist previously (had Symantec Corp. 9.1, w/Exch module). It started last Monday, as soon as the clients started their week after I completed the install over the weekend. This network also has another node at another location, connected via VPN. 2nd DC sits at that site, 2K3 Server; all XP clients. That remote server is set up as the mirror for that node. The remote site saves virtually nothing back to the main office- they keep their work on their local server. No issues at this site at all. Main site also has a 2K3 Terminal Server running- it runs their accounting app. No issues on this box at all, or with either site connecting to it or using it. Server is thoroughly patched; 2kSP-1; Exch SP2; SBSsp1; etc. Clients are also thoroughly patched and up to date. I installed IARSN Task Info 6.2.2 to be able to drill down into the processes, and see what's happening. Everytime it happens, AMON is the process using the resources. When it finally gives up, everything returns to normal. I'm really tearing my hair out on this one. I have EntEdition running at about 6 other sites with no issues at all. Thoughts??