"With ActiveSync 3.x and 4.x and Windows Mobile Device Center (WMDC) you need to create a partnership between your Windows Mobile device and your PC in order to sync. The partnership contains the information about what information you are synchronizing between your device and your PC. This FAQ covers important information about these partnerships."Chris De Herrera has a little FAQ which points out some of the under workings of the two most troublesome applications ever conceived. I would have made the title "Understanding Why ActiveSync or WMDC Partnerships Hardly Ever Work". Seriously though, I have used the registry keys he sites to clean up a lot of partnership debris. It is worth a read.