I've got an iMac running Lion and Office 2011. Somehow I seem to have way too many Calendars. It you look at my attachment you will there are two basic categories of calendars. I've got one category called Calendar and one called On My Computer. This iMac replaced a pc running office 2010. There I had my outlook calendar and I had created an extra folder into which I copied only those contacts that I wanted on my iPhone. I didn't want all my contacts on my phone. That worked fine. I do not remember creating a separate iPhone calendar. In the first category, there are sub-categories called No Category (for appts with no category, I guess and I seldom categorize), Calendar, Home, and iPhone. What are the differences between these? When I was setting up my iMac I imported outlook data into ical and then decided I really wanted to use office for the mac. What is the different between the first main category, Calendar and the second On My Computer? Which Calendar should I use? Complicating it further is the fact that not all calendar entries are on every calendar. If I choose just one I'll be missing entries, but choosing all gives me duplicate entries. It appears if I just check off No Category and Home under Calendar (the first main category) I get the appointments I want with no duplicates. Call me confused.