I encountered similar problem when my Personal pst file corrupted due to unknown reason and also i didn't even had backup of my pst file, after that i asked many friends and i didn't get any solution. Someone suggested me to use Remo repair Outlook software which helped to get back my corrupted pst file. After that i decided to maintain backup of pst file so i used their product called Outlook backup and migrate software which helps to keep backup of Outlook file and another benefit is, it migrates pst file from one version to another Outlook version or from one Windows OS system to another windows system.
For your thread, solution is to use Remo Outlook backup and migrate application helps to backup Outlook file along with all Outlook attributes and to
backup outlook settings, it has a built-in scheduler which backup Outlook automatically as per the scheduled time. You can also
download demo version to check it's functionality.
I think it is best solution to backup pst files.
thank you