My MacBook Pro always responds to invitations and calendar events as if in South Africa. I live in Arizona, have tried setting the date and time set to apple time in either Pacific time, Arizona, or Mountain time. It still responds and sets the calendar event to a S Africa time (meeting at 12.00pm will show up in calendar at 6.00am, etc). Anyone else have this problem? When Apple contacted, they didn't have any good answers, just suggested the date and time be revised in System Preferences.