I work in video post production with 2 separate 2.66GHz Dual-Core Intel Xeon Mac Pros with OS X 10.4.11. Our media is stored on various LaCie and G-Raid 500GB hard drives connected via FW800. In the past couple weeks, I have been experiencing a really strange problem of our drives spontaneously unmounting themselves and causing the "Device Removal Error" to pop up. This first happened repeatedly during an attempt to consolidate an FCP project to one of our LaCie drives on one system. Then it happened again during a different procedure on the same tower but with a different LaCie drive connected directly to the tower via the front port (the first drive to eject itself was at the end of a daisy chain preceded by one or two G-Raid drives).
What is really puzzling is that this problem has since happened again on the 2nd tower with one of our G-Raid drives while using After Effects. This was the only external device connected to the tower in this case.
Of course after the first two unmountings, there were a number of possible explanations but now that the problem has spanned two separate systems, I wonder if the problem is some kind of bug with a recent update of OS X. We've been using these systems for months without issue until very recently, and it would be one hell of a coincidence if these three occurrences were unrelated.