OST files allow Outlook to function offline and immediately sync with Outlook whenever it has access to an internet connection. It may also be utilized in an exchange setting with an MS exchange server. This allows customers or users to create, delete, read, and respond to emails while offline.

PST mode, on the other hand, cannot be utilized on an MS Exchange server but may be found on other servers. In fact, HTTP and IMAP use only PST folder files. Your mails, journals, contacts, calendars, and various other mailbox components that are saved locally are also stored in the PST format.