Over on creativecow.net, we've recently seen corroborative posts about FCPHD suddenly causing online media files to vanish; gone without a trace. Sometimes it happens when the application is actually running or, on a relaunch, the operator gets the reconnect media box asking for stuff that should be online.
Impossible to tell yet if this is FCP or the MacOS at fault.
I cannot overstate the most disturbing aspect: The files are gone without a trace; they never existed. Directory and file recovery attempts have been negative.
I have no personal experience with this phenomenon, I hope we never do.
bogiesan