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How to Open a .mime File

A .mime file is an email in the format email actually travels in: headers, then the body, then any attachments, all encoded as text. It is the same thing as a .eml, just wearing a different name.

.mime .mht .mhtml
Open it on this site

Why it will not open

  • Nothing is registered to the extension. .eml is associated with a mail client on most systems; .mime usually is not, so double-clicking does nothing useful.
  • Opening it in a text editor shows the structure but not the content — attachments are Base64 blocks, and non-Latin subject lines appear as sequences like =?UTF-8?B?...
  • Mail clients can often open it, but only if you rename it first, which is not obvious.

How to open it

In your browser

  1. 1 Open the EML viewer on this site — .mime, .mht and .mhtml are the same MIME structure and are all accepted.
  2. 2 Drop the file in. It is parsed in your browser with no upload.
  3. 3 Headers are decoded, including Base64-encoded subject lines, so Japanese and other non-Latin subjects read normally.
  4. 4 Attachments are decoded from Base64 and can be saved individually or as a ZIP.

With a mail client

  1. 1 Rename a copy from .mime to .eml.
  2. 2 Open it with Thunderbird, Apple Mail or Outlook — all of them handle .eml.
  3. 3 This works because the contents were never different; only the extension was.

.mht and .mhtml are related but not identical

Those are saved web pages using the same MIME container — a single file holding the HTML plus its images. They open in most browsers, and the EML viewer will show their structure, but they are pages rather than messages.

Formats that turn up in the same situation

Not sure what your file is? Identify it

Frequently Asked Questions

Is .mime the same as .eml?
In practice, yes. Both hold an RFC 822 / MIME message. The extension differs because whatever produced the file chose a different name.
Why is the text full of =?UTF-8?B?
That is RFC 2047 encoded-word syntax, used because email headers were historically limited to ASCII. A viewer decodes it back into readable text.
Can I extract the attachments without a mail client?
Yes. They are Base64 blocks inside the file, and any MIME parser can decode them — including the viewer here, which does it in your browser.

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