I have a strange behaviour on my Mountain Lion. I'm using calendar and Microsoft Outlook (via Parallels) on my Mac Book. Calendar and Outlook are connected to my Microsoft Exchange Server system. No iCloud sync with my iPhone4. When I'm now creating a new calendar item with a reminder in Outlook or in OSX Calendar I receive several reminders in the Outlook drafts container. When I open Calendar I receive the following message:
<<"Event" has attendees witch are not recognized by the server>> (Sorry freely interpreted from German).
Has anybody a similar behaviour? Can anybody help?
In the Calendar application, open preferences and remove your Exchange account. Open System Preferences and open Mail, Contacts, & Calendars. There I had two Exchange accounts. Remove the inactive one and enable Calendars & Reminders on the remaining account.