How to export an email as .eml,
from every client that matters.

Gmail's web client doesn't advertise the export feature, but it's there: every message has a "Download message" option tucked inside the three-dot menu. The result is a clean .eml with headers intact — exactly what you want for forensic preservation.

Two notes before you begin. First, the labs experiments and add-ons that occasionally appear in the Gmail interface have, in years past, removed or relocated this option; if you've installed third-party extensions, disable them and try in an incognito window. Second, Gmail strips a few headers from messages it considers spam — those will be exported with the spam-trap chain visible, which is usually what investigators want.

1. Open the email you want to export. Wait for it to fully render — Gmail loads embedded content asynchronously and a partial render can produce a partial export.
2. Click the three-dot menu (kebab icon) at the top right of the message, just left of the reply-arrow.
3. Choose Download message. Your browser downloads an .eml file named after the subject.

The Gmail mobile apps — both iOS and Android — do not provide a way to export a message as .eml. This isn't an oversight you can work around with a setting; the feature simply isn't shipped. Anyone who tells you otherwise is either using a third-party client or talking about a forwarded copy, which is not the same artifact.

If you're on the road and need to preserve a message, the practical path is: forward it to yourself, then open the forwarded copy on a desktop later and export from there. This degrades the headers — your forwarded message gets a new envelope, with new Received chains added on top. The original sender, subject, and body remain, but if forensic provenance matters, that loss is meaningful.

1. If forensic-grade headers matter, wait until you have desktop access. Don't forward.
2. If you must act now, open the message and tap the three-dot menu, then Forward.
3. Send to yourself. Note that the resulting .eml (when later exported on desktop) contains the original message as a quoted body, not as a structurally preserved RFC 822 envelope.

The desktop Outlook clients (Windows, Mac, and the new unified Outlook) have always supported export, but the formats and labels have shifted across versions. The native format is .msg — Microsoft's proprietary container — and most exports default to it. .msg is supported by MailToPDF, but if you have the choice, .eml is more portable and easier to verify against the wire format.

On Windows, the path is straightforward. On Mac, the new Outlook reorganized the export menu — older guides on the internet point to commands that no longer exist. The path below is current as of the 2025 client.

1. Open the email. Select File → Save As on Windows, or drag the email out of the message list on Mac.
2. In the save dialog, change the Save as type to Outlook Message Format — Unicode (*.msg) if you want native, or Text Only (*.txt) as a last resort. For .eml, drag the message to your desktop or a folder window — Outlook writes .eml when dropped to the file system.
3. Verify the resulting file is non-empty and ends with the right extension. Some Outlook builds drop the extension on Mac drops; rename the file with .eml if needed.

Microsoft's web Outlook is, in many ways, the cleanest path. The export option is in the same three-dot kebab as Gmail, and it produces a real .eml with the full envelope intact. The two web variants (consumer outlook.live.com and enterprise outlook.office.com) have the same UI for this feature.

1. Open the message. Click the three-dot menu (More actions) at the top of the message header.
2. Hover View. From the submenu, choose View message source if you want to confirm the headers visually first, or skip directly to step 3.
3. Select Save as → EML. The file downloads to your default location.

Apple Mail offers two ways to export — and one of them produces an .eml directly, no intermediate step required. The undocumented but reliable method is dragging.

1. Open Mail and select the message in the message list.
2. Drag it out of the window onto your desktop, or any Finder folder. Mail writes a real .eml file with the original subject as the filename.
3. Alternatively: File → Save As, then in the format dropdown choose Raw Message Source. This writes a .eml with a different default name, but identical content.

Thunderbird is the most forensics-friendly mainstream client. It exports .eml as a primary format, supports drag-and-drop, and lets you batch-export entire folders. If you do this work regularly, Thunderbird is worth installing and pointing at your IMAP account just for the export workflow.

1. Single message: right-click and choose Save As. Or simply drag from the message list to the desktop.
2. Many messages: select the messages (Cmd-click / Ctrl-click for multi-selection), right-click, and choose Save As. Each message writes its own .eml.
3. An entire folder: install the ImportExportTools NG extension. Right-click the folder in the sidebar, choose ImportExportTools NG → Export all messages in the folder → EML format. A folder of .eml files appears at the destination of your choice.

ProtonMail's privacy-first design extends to export: every message, including end-to-end encrypted ones you've received, can be downloaded as .eml in decrypted form (Proton handles the decryption locally, then writes a plain RFC 822 file).

Export works in the web client and the desktop apps. There is no export option in the iOS or Android Proton apps as of 2025; if you need a forensic-grade export, switch to a desktop client.

1. Open the message in the Proton web client at mail.proton.me.
2. Click the three-dot More options menu in the top toolbar of the message.
3. Choose Export. A standard browser download is initiated; the file is a decrypted .eml.

Yahoo Mail does not provide a direct .eml export from its web interface. The workaround that actually preserves the headers is to enable IMAP access and pull messages with a desktop client (Thunderbird being the easiest), then export from there.

If IMAP setup feels heavy for a one-off export, the lighter alternative is to forward to a Gmail or ProtonMail address you control, then export from those clients. As noted in the Gmail mobile section, forwarding mutates the envelope — the chain-of-custody narrative becomes "this message was forwarded from Yahoo to Gmail and then exported", which is more complex but still defensible if the forwarding is documented.

1. In Yahoo Mail settings, enable IMAP access for third-party clients. Generate an app password — Yahoo requires this for security; your regular password will not work.
2. Open Thunderbird (or any IMAP client). Add the Yahoo account using the app password.
3. Once messages have synchronized, follow the Thunderbird instructions above to export individual .eml files.

Fastmail, like Thunderbird, was built for users who care about email as a portable artifact. Export is first-class: every message has a download option, every folder has a bulk-export option, and the resulting files are clean .eml with the original envelope.

1. Open the message at app.fastmail.com. Click the three-dot menu in the message header.
2. Choose Download. The file is named after the subject and lands as .eml.
3. For bulk export of an entire folder, go to Settings → Backups → Backup or restore mailbox. The download is a tarball of .eml files structured by folder.