Currently Being ModeratedDec 10, 2013 9:22 AM (in response to JAAPrins)
This issue has been discussed extensively here, and you should search for some threads, perhaps using the keywords "missing appointments" or "Outlook appointments".
We have a multi-page set of calendaring best practices we give our users. In our best practices, we tell users to make changes to the calendar from ONE device only, ideally the desktop, or even better OWA. The more changing calendar end points you have the greater the complexity of sync and the greater the possibility of problems arising.
Currently Being ModeratedDec 11, 2013 8:28 AM (in response to JAAPrins)
Check this out. My comments summarizes most of the stuff in the best practices document