A warning and complaint to all:Offline support in Mail.app in 10.5.1 (and 10.5.0) is a DISASTER! Actions performed offline (filing) DO NOT get synced when you connect back up. Further, every time you send a message it warns you that you're not connected! I lost 2 hours of email work on the plane. Apparently only 50% of the 40 emails I sent actually found their way out, I can't tell what is what, and who has seen whom. It's a disaster. DO NOT USE mail.app for offline.darn it.