For me, the synchronization between HTC contacts and the Google online contacts was causing a problem: contacts (generally those with categories) are removed from the phone and moved to the online contacts. Here is how to fix that. First, if anyone has used HTC Sync (as I did before going to CompanionLink), clear out all the data it put into contacts and into calendar. Do that as follows: Settings | Applications | Manage Applications | Calendar Storage | Clear Data and Settings | Applications | Manage Applications | Contacts Storage | Clear Data If you have attempted to use CompanionLink before doing that, also go to the SD card and use a file manager to delete the clusb directory on the SD card if it exists. That clears CompanionLink data and you can make a fresh start. Next, disable Google Contacts sync on the phone as follows. On Settings | Accounts & Sync: check Background data; check Auto-sync; then hit Google. Uncheck Sync Contacts (and Sync Calendar if they don't want that to sync). Hit the back key to return to the previous screen. Uncheck Auto-sync if desired.