Did the sony happen to come with XP SP2? It seens that other people are having the same problem with other firewire devices as well (DV cameras and such) Also, have you any other firewire devices that work, or that you could try? Microsoft is supposed to have some sort of fix for this, although I was unable to find it. Try windowsupdate.microsoft.com and make sure you look at the optional updates. I would also try the m-audio site for any info there.