There is no networking issue with older OS, the issue you are seeing are hardware / software related, there are more people without networking issue than people with them.I now have over 100 win 7 workstations on networks connecting to servers from 2000 to 2008, to linux boxes, to NAS boxes.We have no issues what so ever that are not solve by replacing old nonsupported gear (routers / switches / network cards)My architect customers move VAST amounts if data day it and day out.with a x64 OS things that work under 32 bit can be flaky (this is a drivers isse in most cases)if you have Nvidia chipset MB I would start there, as Nvidia has not gotten the kinks worked out (search here or google to see that) I may not have been clear about my findings here. I am not talking about an environment where actual Windows Server OSs are providing file shares, regardless of version. I'm talking about strictly peer-to-peer networking, with no actual server OSs or domains involved. The file share is being served from the Windows 7 machine, not a real Windows Server OS. And also there is no domain server to assist with authenticating users, either. I can't prove or say conclusively that it's due to non-Windows 7 clients, but it does seem to be supported by actual observation and by other reports on the web.In my small peer-to-peer network (one desktop with a file share serving one other desktop and two laptops), only the client with Windows 7 on it has no issues connecting to the file share. When the problem occurs, the two XP clients can't connect and the Windows 7 laptop has no trouble at all.I don't believe it's the switch/router, because all machines are going through the same switch (including the Win7 client that has no problems). The XP clients both have different network cards (one is a laptop the other is a desktop). Yes, the desktop has an NVIDIA chipset, but the laptop does not.Again, in my observation the problem only affects clients that are not running Windows 7. This is consistent with the original poster (Ken C.), who in his 3rd post revealed that his client is an XP machine too. A Linux user in this thread also reported the problem. I've never seen the problem reported by someone connecting FROM a Windows 7 machine TO another Windows 7 machine. I've Googled several posts and forums on the net, and there is a definite trend that it's seen when Windows 7 (or Vista) is serving files peer-to-peer and the clients are not running Windows 7.