How to open a .msg file without Outlook

Five ways to open Outlook .msg files on Windows, macOS, Linux, iPhone and Android — including a browser method that needs no software at all.

You have been sent a file ending in .msg, you double-click it, and your computer either does nothing or offers to open it in a text editor that shows a wall of binary garbage. This is not a broken file. It is Microsoft Outlook's private format, and almost nothing outside the Microsoft ecosystem knows how to read it.

Why .msg files will not open

A .msg file is not a text file with a different extension. It is a Compound File Binary Format container — the same OLE2 structure that older .doc and .xls files use. Inside it, the subject, sender, recipients, body, and every attachment are stored as separate internal streams, each keyed by a numeric MAPI property tag.

Because Microsoft never published it as an interchange standard, Apple Mail, Gmail, Thunderbird and mobile mail apps all decline to open it. On macOS, double- clicking a .msg file typically produces "There is no application set to open the document". On Android and iOS it usually downloads and then sits there, untouchable.

Method 1 — Open it in your browser (no software)

This is the fastest route and works identically on every operating system, including phones and locked-down work machines where you cannot install anything.

Go to the viewer on the home page.
Drag your .msg file onto the drop zone, or click to browse.
The message opens immediately, with formatting, inline images, recipients and attachments intact.

Because parsing runs entirely in your browser, the file never travels over the network. You can confirm this yourself: open your browser's developer tools, switch to the Network tab, and open a file — you will see no upload request. Or simply disconnect from the internet after the page has loaded and keep working.

Method 2 — Open it in Outlook

If you have Outlook for Windows or Mac installed, double-clicking usually works. If Windows opens the wrong program, right-click the file, choose Open with, pick Outlook, and tick Always use this app.

The web version of Outlook (outlook.office.com) cannot open .msg files. A common workaround — attaching the file to an email to yourself — does not help either, because the attachment stays a .msg that the web client will not render.

Method 3 — Convert to .eml and use your normal mail app

.eml is the standard RFC 822 format that every mail client understands. Converting gives you a file you can open natively, forward, archive or import.

Open the .msg file in the viewer.
Choose Export → Save as .eml.
Double-click the downloaded file. Apple Mail, Thunderbird and Windows Mail all open it directly.

See the full comparison of .msg and .eml for what is preserved and what is not.

Method 4 — Save it as a PDF

For sharing, filing or attaching to a legal or support ticket, PDF is usually the right destination. The step-by-step guide covers how to get a clean PDF that keeps the header block and expands link URLs.

Method 5 — Rename to .txt (diagnostic only)

Renaming the file to .txt and opening it in Notepad or TextEdit will show scattered readable fragments among binary noise. Attachments, formatting and non-Latin characters are unrecoverable this way. Treat it as a way to check that a file is not empty, not as a way to read a message.

Opening .msg files on a phone

Neither iOS nor Android has a built-in handler. On both, the reliable path is to open the file in a browser: tap the attachment, choose Share or Save to Files (iOS) / Download (Android), then open the viewer and pick the saved file. The interface adapts to small screens and attachments download to your normal downloads folder.

What about multiple files?

You can drop up to 50 files at once. They appear in a list you can filter and step through with J and K, which is considerably faster than opening an exported mail archive one file at a time.