How to open a PST file without Outlook

A .pstfile is Outlook’s Personal Folders file: a whole mailbox, or an archive of one, in a single file. It is a database format, far more complex than a single .msg message, and this site does not read it directly. Formats and limits explains why: a parser that opened some PST files and silently lost messages from others would be worse than none.

What works today is a two-step route. Convert the .pst into MBOX files with readpst, a free, open-source tool from the libpst project (libpst), then open those files in the MBOX viewer here. readpst runs on your own computer and the viewer runs in your browser, so the mailbox is never uploaded anywhere.

Open the MBOX files →Search, read and export the converted folders.Convert the messages to PDF →If you chose separate .eml files instead.

1. Install readpst

On a Mac

readpst is in Homebrew as part of the libpst formula, with ready-built versions for Apple silicon and Intel Macs (Homebrew). With Homebrew installed, run this in Terminal:

brew install libpst

On Debian or Ubuntu Linux

readpst comes in the pst-utils package (Debian manual pages (pst-utils)):

sudo apt install pst-utils

On Windows

On Windows, run readpst inside the Windows Subsystem for Linux, which gives you the same Ubuntu package as above. Microsoft’s instructions: open PowerShell as administrator, run wsl --install, and restart. That installs Ubuntu by default, and needs Windows 10 version 2004 or later, or Windows 11 (Microsoft Learn). Then, in the Ubuntu window:

sudo apt update
sudo apt install pst-utils

Inside WSL your Windows drives appear under /mnt, so C:\Users\you\Documents is /mnt/c/Users/you/Documents, and explorer.exe . opens the current Linux folder in File Explorer (Microsoft Learn).

2. Convert the PST to MBOX

Make an empty folder for the output, because readpst requires the output directory to exist already, then run readpst with -r for recursive output and -o for that folder (readpst manual):

mkdir pst-out
readpst -r -o pst-out archive.pst

On Windows, inside WSL, point it at the files on your C: drive:

mkdir /mnt/c/Users/you/pst-out
readpst -r -o /mnt/c/Users/you/pst-out /mnt/c/Users/you/Documents/archive.pst

The result mirrors the PST’s folders: a folder for each one, named as in Outlook, with that folder’s email in a file called mbox inside it. Appointments, contacts and journal entries are written to separate files named calendar, contacts and journal (readpst manual). Those three are not email and do not open in the MBOX viewer.

Other options from the same manual that are often useful:

Useful readpst options
Option	What it does
`-r`	Recursive output: a folder for each folder in the PST, each holding a file called mbox.
`-o dir`	Where to write the output. The directory must already exist.
`-D`	Include deleted items in the output.
`-8`	Write message bodies in UTF-8 where a UTF-8 version is available.
`-t e`	Process emails only, leaving out appointments, journal entries and contacts.
`-e`	Write each item as a separate file with an extension (.eml for email) instead of mbox.

3. Open the MBOX files

Open the MBOX viewer.
Drop in the mbox file from the folder you want, for example pst-out/Inbox/mbox. It has no extension, and does not need one: the viewer recognises a mailbox from its contents.
Search by sender, subject or date, open any message with remote images blocked, and export the ones you need as .eml files, a new .mbox, a PDF, or just their attachments.

If you converted with -e instead, each email is its own .eml file: open one in the EML viewer, or drop a whole folder of them on EML to PDF or the attachment extractor.

What to expect

Each Outlook folder becomes its own mailbox, so a PST with many folders becomes many files. Open them one at a time.
The MBOX viewer holds one mailbox in your browser’s memory while it is open. A folder of a few gigabytes is fine in Chrome or Edge on a desktop and may be too much for Safari or a phone; the viewer warns you before it starts.
readpst is separate software, maintained by the libpst project rather than by this site. If it cannot read a particular file, its project page is the place to look (libpst).
For a single Outlook message saved on its own, you do not need any of this: see how to open a .msg file.

Sources

Each platform step above comes from the vendor’s own documentation, listed here. Steps we could not find documented by the vendor are left out rather than written from memory.

libpst: libpst project home page
Debian manual pages (pst-utils): readpst(1): convert PST (MS Outlook Personal Folders) files to mbox and other formats
Homebrew: libpst formula
Microsoft Learn: How to install Linux on Windows with WSL
Microsoft Learn: Working across Windows and Linux file systems