I have a similar problem and have posted it on a few forums with no response. My problem is that when I installed 10.4 (Tiger), I did a clean install after backing up my old Mac HD (by copying it on another HD). When I open up my old database, no matter what version of entourage, and in spite of both basic and advanced rebuilds, all the subfolders I created are still there, but all the e-mails inside them are gone. I suspect that there is some set of preferences that were on my old HD that are not on this new (i.e. reformatted) HD, and the lack of these preferences is not allowing me to see the e-mails in the subfolders. I don't know where these preferences may be so that I can copy them. It may be another reason for this problem. Naturally, I need these old e-mails back.