How to Open Outlook PST and OST Files Without Outlook

Description and use

Users can open PST/OST files without Outlook using libpff, readpst, Thunderbird, or client‑side browser viewers, maintaining data control.

Problem

Need to read PST/OST files without having Outlook installed, especially on Linux or macOS.

Outcome

Users can access PST/OST files locally on Linux/macOS using open‑source tools, preserving privacy and enabling long‑term archival or forensic analysis.

Workflow

• Identify file type and format with pffinfo or by extension and size.
• Make a copy of the file before processing.
• Decide whether data can be uploaded or must stay local.
• Choose a tool: - Outlook if available and same profile. - libpff/pffexport for forensic extraction. - readpst to convert to MBOX/EML for Thunderbird. - Client‑side browser viewer (e.g., Mailward) for quick local viewing. - Upload‑based converters only if privacy is not a concern. - Verify results by comparing folder counts and spot‑checking messages. - Clean up exported data securely after use.

Evidence

Sooner or later someone hands you a .pst file. Maybe it's an old mailbox export from a former employee, an archive from a laptop you retired years ago, or evidence you need to review.

Source

libpff by Joachim Metz is a forensic‑grade library for PST, OST, and PAB files. It ships with command‑line tools: pffinfo shows file metadata; pffexport extracts the contents into a directory tree.

Source

readpst comes from the libpst project. Its main advantage is that it converts to standard formats that ordinary mail clients understand.

Source

Mailward parses PST/OST files locally in a Web Worker with no upload, handles multi‑GB files, and shows the folder tree, message bodies, and attachments, with full‑text search.

Source