KB: Why OWA or EWS application doesn’t show yearly recurring appointment?

While working with one of my customer we noticed that the yearly recurring appointment doesn’t show in Outlook Web Access or Exchange Web Services(EWS) application.

Customer created a monthly or yearly recurring appointment. He set the request to occur on the second, third, or fourth weekday of a month. But, whenever we use Outlook Web Access (OWA) client or customer’s Exchange Web Service (EWS) application to view this request, the request is set to occur on the first weekday of the month; but strangely, the Outlook 2007 client displays the appointment correctly. When we do the troubleshooting, this happens for Exchange Server 2007 SP1 Roll up 4.

We recommended customer to install the latest service pack (during the time it was Update Rollup 7), which resolved the issue.