Thanks Amaranthe, I disabled the virus scanner while I'm trying to solve this issue. The files are jpgs averaging 4-5 meg. (All the pictures I've taken with my Canon 40D) I swapped the switch, and now more often that not I get the other error, "Too many files are currently in use. Quit one or more programs and then try again." It has no problem with big files. I can copy 25 gig of 3-4gig .iso files with errors. It chokes on smaller files. I also noticed if I go over to the the source machine, it's slowing way way down during the copy. Many of its tasks become unresponsive until the copying ends. Strange, it doesn't make sense that the source machine would go cripple when feeding the Win 7 machine. I mean it's simply streaming packets down an an Ethernet port and should have no idea what OS the other machine is running, right? Also, the problem is reproducible when The Win 7 machine copys from any machine on the LAN. This is perplexing. I really wanted to like Windows 7... Thanks again, KenC