Archive PST files should ideally be saved on a system other than the one a user regularly works on. This helps ensure the safety of such files in case any disaster befalls the system. To access an archive PST, all a user needs to do is import the file into Outlook using the Import & Export Wizard.How do I open an Outlook pst file?
Open an Outlook Data File (.pst) If you have an Outlook Data File (.pst) that doesn't appear in the Navigation Pane, you can add it so that you can work with the items in the data file. On the File tab, click Account Settings > Account Settings. On the Data Files tab, click Add.