Convert PST to MBOX

Steps

1. Open Letterlark and open your .pst file. Large files take some time to index – the progress bar shows how far it is.
2. Choose a folder on the left (for example Inbox) or keep “All files”. Use search or date filters if you only need part of the mailbox.
3. Click Select all results, then Export → MBOX.
4. Import the .mbox file: in Thunderbird with the ImportExportTools NG add-on, or in Apple Mail with File → Import Mailboxes.

What is included

• Sender, recipients, subject, date and Message-ID.
• Plain-text and HTML bodies (HTML that Outlook stored as RTF is converted back to HTML).
• All attachments, and attached emails as embedded messages.
• Each export is one .mbox file in standard mboxrd format, so lines starting with “From ” are escaped correctly.

Free version and license

Without a license you can export 20 messages at a time, which is enough to test the result in your mail program. For a whole mailbox, a one-time license removes the limit. Export one folder at a time if you want to keep the folder structure, because an MBOX file holds one folder.