Personal folders are represented in the Windows operating system by the. Outlook personal folders are very useful as they allow us to create offline copiers of our mail, contacts and tasks for offline access, data backup or transfer to a different computer. Could you elaborate more about how to insert Outlook data files and using them for daily archiving of my mailbox? I love MAC OSX Sierra and wish to use Outlook on the MAC, so i guess other question i have is whether i can use pst on MAC OSX. Greetings Easytweaks team! A co-worker told me that he is using pst files in order to keep backups of his email box, calendar, journals and contact people.