How to open a .msg file in Gmail

Gmail cannot open .msg attachments. Why not, and the two reliable ways to read one — including converting it to a format Gmail does display.

Someone forwards you a .msg attachment in Gmail, you click it, and Gmail either offers to download it or shows "No preview available". Gmail has no .msg support and is not going to add it. Here is what to do instead.

Why Gmail cannot preview .msg files

Gmail previews formats it understands — PDF, Office documents, images — using Google's own converters. .msg is Outlook's proprietary binary container, not a document format, and Google has never implemented support for it. You get "No preview available" and a download button.

Uploading the file to Google Drive does not help either, for the same reason: Drive stores it happily but cannot render it.

The quickest route

Download the attachment from Gmail.
Open the viewer in another tab.
Drag the file onto it.

The message opens with its formatting, inline images and attachments intact. The file is parsed inside the browser, so it is not uploaded to us — which is worth noting when the message arrived at a work address.

If you need it back inside Gmail

Gmail does display .eml attachments, so converting solves the problem properly:

Open the .msg file in the viewer.
Choose Export → Save as .eml.
Attach the .eml to a Gmail message instead.

Recipients can then open it directly. The conversion guide covers what is preserved and what is lost.

Forwarding a .msg to someone else

If you forward the .msg as-is, whoever receives it hits exactly the same wall unless they have Outlook. Converting to .eml first is the courteous option — it opens natively for essentially everyone, including the person reading it on a phone.

Why the file arrived as .msg in the first place

Usually because the sender dragged a message out of Outlook onto their desktop, or used File → Save As, which produces .msg by default. Outlook's own Forward as attachment also attaches messages in this format. None of that is deliberate — most senders do not realise the file is unreadable outside Outlook.