FYI, I have been using this program to sync successfully between Entourage and a Treo 600 (ATT/Cingular) for over a year. My Entourage database file is large (6000 contacts and thousands of calendar events), and it has been flawless. When I upgraded to Tiger, it continued to work fine. However, when I then switched to a Treo 650 (Verizon), the Entourage conduit failed. After trying many times to fix this, I contacted Microsoft who then admitted that this was a known problem, and they are not sure why. They claimed they are working with Apple and Palm to resolve this, but gave no date for a fix. They suggested checking the Microsoft Mactopia website for notifications of updates on a fix.