Question 1

How do I open a PST file on a Mac?

Accepted Answer

Open it here in Safari or Chrome - nothing to install. Outlook for Mac can import a PST but cannot simply open one to read, and cannot use an .ost at all. To move the mail into Apple Mail, save each folder as .mbox and use File, Import Mailboxes.

Question 2

Can I convert PST to MBOX or EML?

Accepted Answer

Yes. The .mbox button saves every message in the open folder as one mailbox file that Thunderbird, Apple Mail and most mail tools import, and .eml saves the message you are reading as a standard email file, attachments included.

Question 3

How big a PST file can it open?

Accepted Answer

No set limit. The file is read in place, a slice at a time, instead of being loaded into memory, so a mailbox of many gigabytes opens without filling the computer’s memory. Exporting a very large folder as .mbox does build that file in memory, so a folder of many thousands of messages is best exported on a computer rather than a phone.

Question 4

What is the difference between a PST and an OST file?

Accepted Answer

A PST is a standalone mailbox file - exported, archived or used by a POP account. An OST is the local copy Outlook keeps of a mailbox that lives on a server, such as Exchange, Microsoft 365 or Outlook.com. Both hold the same kind of content, and both open here.

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