How do I open an EML file without Outlook?

Install Thunderbird, which is free and opens EML directly. For a quick look at the text you can also rename the file to .txt and open it in any editor, since EML is plain MIME text.

What is the difference between EML and MSG?

EML is the open RFC 5322 format that nearly every mail client can read. MSG is Microsoft Outlook's proprietary format for a single saved message and needs Outlook or a dedicated viewer.

File extensions

How to open a .eml file

Email message file · Email

An .eml file is a single saved email in plain MIME text. Thunderbird and Outlook open it directly, and in a pinch you can rename it to .txt and read it in any editor.

What a .eml file actually is

EML is the RFC 5322 message format written to disk: headers, then a blank line, then the body, with attachments encoded as base64 MIME parts. It is the standard way to export one message from almost any mail client.

Because it is text, an .eml is unusually transparent. The full headers are right there, which makes it the format of choice when someone needs to inspect the actual routing of a suspicious message.

Why it will not open

If no desktop mail client is installed, nothing claims the .eml association, which is increasingly common now that most people use webmail exclusively.

Step by step

Windows

01If you have Outlook or Thunderbird, double-click the file and it opens as a message.
02With no mail client, right-click, choose "Open with", then "Choose another app", and pick Notepad. Headers and body text are readable immediately.
03To read it properly with formatting and attachments, install Thunderbird, which is free, and drag the .eml into it.

macOS

01Double-click. Apple Mail opens .eml natively.
02To inspect the raw source instead, right-click, choose Open With, then TextEdit.

What usually goes wrong

The headers are the point in a phishing check

Opening an .eml as text shows the full Received chain, Return-Path and authentication results. That is how you tell whether a message claiming to be from a bank actually came from it. Reading the headers is safe; opening the attachments inside is not.

EML and MSG are not the same

MSG is Outlook's proprietary single-message format. EML is the open standard. Most clients read EML, far fewer read MSG.

Programs that open .eml

Our pick, in order. Every one links to the publisher's official download URL and the SHA-256 hash of the installer, so you can check the file before you run it.

Common questions

How do I open an EML file without Outlook?: Install Thunderbird, which is free and opens EML directly. For a quick look at the text you can also rename the file to .txt and open it in any editor, since EML is plain MIME text.
What is the difference between EML and MSG?: EML is the open RFC 5322 format that nearly every mail client can read. MSG is Microsoft Outlook's proprietary format for a single saved message and needs Outlook or a dedicated viewer.