Email & Comm • MIME: message/rfc822

.EML File Extension

Standard RFC 822 email file format containing email headers, text body, and file attachments.

Category Email & Comm
MIME Type message/rfc822
Magic Bytes 46 72 6F 6D 3A (ASCII text: From:)
Developer IETF (RFC 822 Standard)
Typical Size 15 KB – 10 MB
Security Risk Medium Risk

Format Architecture & Technical Specifications

EML is an email archive file format developed by Microsoft for Outlook Express and standardized under RFC 822. It contains raw Internet email headers, plain text body, HTML body, and MIME encoded file attachments.

How to Open .EML Files

1 Open in Thunderbird

Drag .eml file into Mozilla Thunderbird or Apple Mail.

2 View in AnyFileX EML Viewer

Drop .eml into AnyFileX online tool to inspect email headers and extract attachments.

Compatible Software Programs

Mozilla Thunderbird

windows, mac, linux • Free

Microsoft Outlook 365

windows, mac • Commercial

Apple Mail

mac, ios • Free

Security Considerations & Verification

EML files can carry malicious email attachments or phishing links. Exercise caution when opening untrusted EML files.

  • Open .eml file in plain text editor (Notepad) to inspect raw MIME boundary delimiters.

Frequently Asked Questions

What is a .EML file?

A .EML file is a RFC 822 Email Message Archive associated with Email & Comm. Standard RFC 822 email file format containing email headers, text body, and file attachments.

How do I open a .EML file on Windows or Mac?

You can open .EML files using Mozilla Thunderbird, Microsoft Outlook 365, Apple Mail. If you do not have native software installed, you can use AnyFileX's free File Identifier or convert .EML to a standard format in your browser.

Is a .EML file safe to open?

This format carries a safety rating of Medium Risk. EML files can carry malicious email attachments or phishing links. Exercise caution when opening untrusted EML files.

Can I convert a .EML file to other formats?

Yes! .EML can be converted to formats such as .PDF, .MSG directly in your web browser.

What should I do if a .EML file is corrupted or won't open?

If your .EML file displays an invalid header or signature error, check its magic bytes hex header (46 72 6F 6D 3A (ASCII text: From:)) using AnyFileX's Magic Byte Detector or follow our step-by-step file repair guide.