Which file extension is used by Microsoft Outlook to store its data?

• A. .docx
• B. .pst
• C. .patch
• D. .email

Answer: (B)

Outlook stores its mailbox data in a file known as a Personal Storage Table. This data file uses the .pst extension and contains emails, attachments, calendar items, contacts, and other mailbox content. It’s the primary local data store for Outlook when you’re using POP or IMAP accounts and can also be used for archiving older items.

In some scenarios (like using Exchange in cached mode), Outlook creates a different offline data file with the .ost extension, which backs the mailbox for offline access and synchronization. However, the standard file format used to store Outlook data on disk is .pst. The other extensions listed don’t represent Outlook’s data storage format.