I have a network with 18 workstations, 10 are XP Pro SP3, 7 are Win7 Pro and 1 is Vista Business. When I try to copy large files (60MB) from Win7/Vista to XP machines the copy fails. I have eliminated networking issues as I connected Win7 machine to Win XP Machine directly to take out the network topology. Same problem. I shut of Norton AV 2010 and restart and it says Norton is off but the problem still exists. I than uninstalled Norton Av 2010 with the Norton Removal tool from a XP machine and the file copy problem is gone. I than reinstall Norton on the XP machine and do all the liveupdates and the copy issue is still gone. After a few days the problem comes back. I did the same procedure again with the same results. There is no problem with copying between WIN7/Vista machines to other Win7/Vista machines. The problem is definitely related to Norton AV 2010. I have no other Virus software installed on any of these machines. I did try loading Microsoft Security Essentials and there is no problem. I can even navigate to an XP Machine and copy the file back to the WIN7 machine with no problem. If I than try to copy back to the XP machine it fails. I am a long time user of Norton products and want to continue to use Norton AV. Please advise