An XstReader alternative that runs in your browser
XstReader is a solid open-source PST viewer — if you are on Windows and can install software. Mailward does the same job in a browser tab: drop a .pst or .ost file and read it on any OS, with nothing installed and nothing uploaded.
What is a good alternative to XstReader on a Mac?
XstReader is Windows-only — there is no macOS build — so on a Mac the realistic choices are a terminal conversion or a browser viewer. The terminal route is readpst from the open-source libpst project, installable through Homebrew; it converts the archive to mbox rather than letting you read it in place. The browser route keeps the two qualities that make XstReader trustworthy — it parses the [MS-PST] format itself, and mail never leaves your machine — while running on macOS, ChromeOS, or a locked-down work laptop: Mailward opens .pst and .ost archives in a tab, parsed locally, with reading, folder browsing, and full-text search free. Where XstReader still wins: it is open source, and as a native desktop app it has no browser memory ceiling. Where the browser approach wins: nothing to install, identical behavior on every operating system, and the same interface also reads OLM, MBOX, EML, and MSG — XstReader stops at PST and OST.
Open this page on any OS — Mac, Windows, ChromeOS, or Linux.
Drop the .pst or .ost file; it is parsed locally, nothing is uploaded.
Browse folders, read messages, and search across the whole archive.
Export one message free, or batch-export folders to MBOX / EML with Pro.
An XstReader alternative that runs in your browser
XstReader deserves its reputation: it is free, open source, and reads PST and OST files properly — on Windows desktops. The gap appears the moment you are on a Mac or a locked-down work machine where you cannot install anything.
Mailward fills exactly that gap: the same read-and-export job, done in the browser with the File API and a Web Worker, so it runs identically on macOS, Windows, ChromeOS, and Linux. Nothing is uploaded — the file is parsed on your own machine, and you can go offline after the page loads.
Reading, browsing, and search are free; batch export to MBOX/EML is the one-time paid step. If you are on Windows and happy installing software, XstReader remains a fine choice — this page exists for everyone else.
On a Mac? macOS ships nothing that opens PST — readpst needs Homebrew and a terminal, and new Outlook for Mac won't export mail files. A browser tool needs no install at all.
Where each tool wins — stated honestly
XstReader is a genuinely good piece of software. It is open source, it reads the [MS-PST] format properly, it is fast, and because it runs as a native Windows application it has no memory ceiling imposed by a browser tab. If you are on Windows and can install what you like, it is a legitimate answer and this page is not trying to talk you out of it.
The gap is entirely about where it can run. There is no macOS build, no Linux build, and nothing you can use on a Chromebook or a managed work laptop that blocks unsigned installers. That is the exact situation most people are in when they discover they have a PST and no Outlook: a Mac, or a machine they do not control.
Mailward covers that case by moving the same job into a browser tab. The privacy property people value in a desktop tool is preserved — the file is read with the File API and parsed in a Web Worker on your own machine, and you can disconnect from the network after the page loads and keep working. What you give up is the native app's headroom; what you gain is running anywhere with nothing installed.
- XstReader platform
- Windows desktop only — no macOS or Linux build
- Mailward platform
- Any modern browser — macOS, Windows, ChromeOS, Linux
- Install required
- XstReader: yes · Mailward: none
- Files uploaded
- Neither — both parse locally
- Pick XstReader when
- You are on Windows, can install software, want a native app
Comparing formats? PST, OST, OLM, MBOX & EML explained — what each one is internally, and what is lost converting between them.
XstReader vs Mailward
| XstReader | Mailward | |
|---|---|---|
| Runs on | Windows desktop only — no macOS or Linux build | Any modern browser: macOS, Windows, ChromeOS, Linux |
| Install | Yes — a desktop application | None — open the page and drop the file |
| Formats read | PST and OST | PST, OST, OLM, MBOX, EML, MSG |
| Where parsing happens | Locally, as a native app | Locally, in a Web Worker — nothing uploaded |
| Memory headroom | Native-app headroom, no tab ceiling | Browser tab — large files read in pages, not loaded whole |
| Open source | Yes | No |
| Price | Free | Read & search free; batch export $19 one-time |
| Pick it when | You are on Windows and can install software | You are on a Mac, a Chromebook, or a locked-down machine |
Before you trust a mail file to a website
Q. How is this different from XstReader?
XstReader is a Windows desktop app you install; Mailward runs in the browser on any OS with no install. Both read PST and OST locally without Outlook — the difference is where they run and what you have to install.
Q. Is Mailward also free?
Reading, folder browsing, search, and single-message export are free. Batch export of whole folders or search results is a one-time $19 license — there is no subscription.
Q. Does my file get uploaded?
No. Like a desktop app, Mailward parses the file on your own machine — in a Web Worker via the File API. You can disconnect from the network after the page loads.
Q. When is XstReader the better choice?
If you are on Windows, can install software, and prefer a desktop app, XstReader is excellent and open source. Mailward wins when you are on a Mac or Chromebook, cannot install anything, or want zero setup.
Free to open, read, search, and export one message. Batch conversion is a one-time $19 licence — no subscription, no recurring fees.
Other formats & archives
Same local-first engine, every common mail format.