Originally Posted by tonysharma
Open the desktop manager once your handheld is connected. Go to BACKUP and RESTORE, ADVANCED, Highlight CALENDER and CALENDER ALL, under Devices Database. With both highlighted 9or one at a time), press the CLEAR button. Disconnect, and reboot the unit. Now Sync.
Best to do a full sync before you do any of this, so as to avoid any potential loss.
Also good to clear out unneeded service books: Options > Advanced Options > Service Book (Look for books ending with [ CICAL ] ) Best to leave one in place as the default service...