When you create a backup of an Outlook email account, it saves to a .pst file. To read that data you will need to import that .pst file into Outlook.
1. Open Outlook and click File
2. Select Account Settings>Account Settings
3. Under the Data Files tab, click Add
4. Navigate to the file location and click OK
5. You data file will now be listed here under Data Files. You will also see the file appear on the left side as your inbox would.
6. If you wish to rename the file to something more recognizable, you can double-click the file under the data files tab and type in a new name