I read about the success others have had with Tiger, that’s why I tried to install it under Tiger. I ran the diagnostics off the install CD and the board checks out fine. The board also shows up in the systems profiler. This was the first time I’ve installed this M100 so, I haven’t even entered the system key yet. When I try to launch it, The M100 window appears for a half second then the error 5551 window comes up. There is no other explanation or anything. As far as the SCSI card, I have an ATTO UL2S which I believe is not compatable with Tiger (it doesn’t show up in the system profiler – even with the latest drivers installed) I just purchased a UL3D to remedy that problem, though.