I also have been having issues with any OS above 10.3.5. I tried 10.3.6, 10.3.9 and 10.4.2. Each time I upgraded, the mac lost the ability to see the SATA Raid drive. No one seems to be able to figure it out. I used the fibre channel utility and set it to what the manufacturer reccomends, did all the software updates, tried a different fibre card, different cables, everything. I'm now back using 10.3.5 and it's working fine. But now I have FCP 5 and Tiger upgrades sitting in the boxes...what to do.