How to open a .msg file on a Mac
macOS has no built-in handler for Outlook .msg files. Four ways to read one on a Mac, including a browser method that needs no software and no upload.
You double-click a .msg file on your Mac and get "There is no application set to open the document". macOS ships no handler for the format, and — unlike on Windows — installing Outlook does not reliably fix it either. Here is what actually works.
Why macOS cannot open .msg files
A .msg file is not a document in any format macOS knows. It is a Compound File Binary container holding Outlook's internal MAPI properties — the same OLE2 structure as a legacy .doc, but with entirely different contents. The format breakdown covers what is inside one.
Because Microsoft never published it as an interchange format, Apple Mail, Mail.app plug-ins, Preview and Quick Look all decline it. Quick Look shows a generic file icon rather than a preview, which is often the first sign something is wrong.
Method 1 — Open it in your browser
This is the only method that needs nothing installed and works the same on an Intel Mac, an Apple Silicon Mac, and a locked-down work machine where you cannot install software.
- Open the viewer.
- Drag the
.msgfile onto the drop zone. - The message opens with its original formatting, inline images, recipients and attachments.
The file is parsed by JavaScript inside the page, so nothing is uploaded. You can confirm that in Safari's Web Inspector or Chrome's DevTools: open the Network tab, then open a file, and no request carries your data.
Method 2 — Convert to .eml and use Apple Mail
If you want the message to live in Apple Mail alongside everything else, convert it to the standard format first:
- Open the
.msgfile in the viewer. - Choose Export → Save as .eml.
- Double-click the downloaded file. Apple Mail opens it directly, and you can then drag it into any mailbox to keep it.
What .eml preserves and what it drops is worth reading if the message is evidence or an appointment rather than ordinary mail.
Method 3 — Outlook for Mac
Outlook for Mac has never handled .msg files as smoothly as the Windows version. Double-clicking frequently does nothing at all. What usually works instead is dragging the file directly into a mail folder in the Outlook window, which imports it as a message you can then open normally.
Note that Outlook on the web cannot open .msg files at all, so a Microsoft 365 subscription on its own does not solve this. Emailing the file to yourself does not help either — it arrives as the same unreadable attachment.
Method 4 — Save it as a PDF for filing
If the goal is to archive the message or attach it to a ticket, PDF is usually the real destination. The PDF guide covers how to get a clean, paginated document with the header block intact.
What does not work
- Renaming to .txt and opening in TextEdit. You will see scattered readable fragments among binary noise. Attachments, formatting and any non-Latin characters are lost. Use it only to confirm a file is not empty.
- Quick Look and Preview. Neither has a handler for the format.
- Changing the extension to .eml. The two formats are structurally unrelated; renaming does not convert anything, and Apple Mail will either refuse the file or show gibberish.
Opening many files at once
Select them all and drag them in together — up to 50 at a time. They appear in a list you can filter, and J and K step between them. That is considerably faster than converting an exported archive one file at a time.