Why can't I see someone's scheduling information (Free/Busy data) in Outlook Calendar after a certain date?
The Free/Busy data (what you see when scheduling people) has a date range that can be controlled by each user. From Outlook, click Tools->Option->Calendar Options...->Free/Busy Options... The first option allows you to change how many months of Free/Busy information is sent to the server. The default of 2 months puts the current month and the next month up on the server.