Hello and I hope you may be of help. I have a Mac Book Pro and a Treo 700p; I previously had a Treo 650. I use Entourage and want to sync my contacts, to do's and calendar. I use Missing Sync and so far, over the last year plus, it has not worked at all to my satisfaction. I often get duplicate contacts, or my calendar items or contacts do not cross form one to the other. I got the Treo to 'simplify' my life and have found it difficult to rely on due to syncing problems. I have tried to work with the Missing Sync staff, but it has not solved the problems.