Hi there, just upgraded to 10.5.4 Leopard. I have a MBP Core 2 Duo 2.33 Ghz, 3 GB Ram and did a fresh install of Leopard then upgraded to 10.5.3 a while back. After upgrading today, I got the "disk you inserted is not readable by this computer" message when I plugged in my LaCie drive via FW800. First I thought the drive was busted, but then I tried attaching via FW400 and it worked. So basically, my Mac can't recognize the LaCie any more now when connecting via FW800 but it can if it's attached via FW400. What gives? Thanks for any ideas. Btw. If anyone had experienced the slow/choppy framerate after the QT 7.5 update in 720p and 1080p apple trailers, 10.5.4 seemed to fix that (they ran smooth as butter after the upgrade).