I am using Outlook 2010 and have set a .pst file (one on my drive) as the default inbox. Though my outlook calendar has appointments on it, when another person is checking my availability on their outlook calendar, it shows me as being free when Im not. I was told that in Outlook 2010, for another person to see my schedule I had to have .ost file as the default inbox. I never had this issue with Outlook 2003 wherein I was using .pst file as the default inbox and my schedule was reflecting correctly on the other persons calendar. Let me know if there is a workaround in Outlook 2010 for this.