Mining local account messages, contact, calendar, and tasks out of Outlook manually is not for the average human to attempt. That requires a very high skill level and E-mail administration expertise. I've done that before, and you rarely get all the data out of the OST file. Part of that has to do with the fact that most Exchange Servers live on a domain-based network, and require a domain network login in order to sink shared account metadata such as shared inboxes and shared calendars. This means that this information can not be mined from the OST and put into a PST for local use, as it has no meaning in a LAN or local standalone PC environment. Automated paid software takes this into consideration and lets you answer questions about the environment the OST exchange file came from; in other words it lets you uncheck domain-based shared metadata from the conversion process and just get partial data such as E-mail messages from a non-shared E-mail inbox, contacts, and non-shared Calendar events. If you took this OST file from your work or from someone else's work, there are literally thousands of GPO's (Group Policy Object permissions) that can be set in the Exchange Server side, that have no direct analogous setting in a PST file. 
I would spend the money on a program that automates this very difficult process for you as much as possible. Just so you know, there are companies who provide this service as an Outsourced Item and specialize in Outlook and Exchange conversions. We used to sell these services to corporate Clients when I was with IBM and Wang, and they are very expensive indeed. After attempting both manual and free-trial software and you get nowhere, you might consider a Paid service that specializes in this sort of thing. 
