So I've been using my Macbook Pro (2010 unibody model) to record music with my Presonus interface via the firewire 800 port. I use a 400 to 800 converter cable to get to it. Before anyone mentions blaming Presonus or the cable I've seen any number of things from hard drives to cameras reported as doing this too, so I highly doubt it's that. I think it's something to do with the computer. Anyone else have any experience with this and were able to fix it?