This article will provide you a couple of quick tips to help resolve issues surrounding freetimebusytime inaccuracies. There are times when a user may report a problem with his busytime information or information for other users who he is scheduling meetings with.
This video deomostrates how to rebuild the Busytime Database used for Calendar and Scheduling.
Meetings, appointments, allday events, and event announcement count as busy time on your schedule. If the calendar doc is flagged "Mark private" it stays busy. With the flag "Mark available" there won't be an entry in the busytime.nsf. Anniversaries and reminders do not count as busy ...