I have a client who is using Outlook 2003 in a Citrix environment (the Exchange server is running 2003 as well). Sometimes when they accept an appointment that they are invited to, it will not show up on their calendar. However, they can see it on their iPhone and they also get the reminder about the appointment through Outlook as well. Also, if they try to double schedule a time, they get the alert that there is already another appointment, however, even then it still doesn't show on the calendar. Outlook is not running in cached mode. Any suggestions?