If your PST file get corrupted or inaccessible, then I would suggest you try Scanpst.exe inbuilt utility provided by Microsoft for Outlook users. The utility easily found corruption issues and fixed that if it possible. But if any major corruption issues occurs then in such case you will be required third party Outlook PST Repair tool. In such situation you can first try the demo version of the software.
To get more details about manual and third party tool visit here: migrateemails.com/2016/06/28/repair-pst-file