View full headers in Outlook

Where Outlook keeps the headers depends on which Outlook you have. In new Outlook for Windows, Outlook on the web and Outlook.com, open the message, click More actions (…) at the top of it, then View → View message details. In classic Outlook for Windows, open the message in its own window, then go to File → Properties and copy the text in the Internet headers box. Then paste it into the analyser.

Microsoft's own page for this is View internet message headers in Outlook; it has tabs for new Outlook, classic Outlook and the web. Microsoft moves these menus often, so if yours doesn't match, look in the message's own "…" menu for anything called details, source or headers.

Which Outlook do I have?

• New Outlook for Windows: looks almost identical to Outlook on the web and has a "New Outlook" toggle in its top-right corner.
• Classic Outlook for Windows: the older desktop app with a File tab at the far left of the ribbon (Outlook for Microsoft 365, 2016, 2019, 2021, 2024).
• Outlook on the web / Outlook.com: Outlook in a browser, whether a work account or a personal Outlook.com, Hotmail or Live address.
• Outlook for Mac and the Outlook phone apps are covered further down.

New Outlook, Outlook on the web and Outlook.com

1. Open the message (in the reading pane or double-click it).
2. At the top of the message, click More actions (the … button next to Reply, Reply all and Forward).
3. Choose View, then View message details.
4. A window opens with the headers in a text box. Click inside the text, press Ctrl+A (Cmd+A on a Mac), then Ctrl+C.
5. Paste into the analyser.

This is the path Microsoft documents for all three. Some versions also show View message source in the same View submenu, which displays the whole raw message rather than just the headers. Microsoft's help page does not mention it, and community reports say it sometimes opens blank in new Outlook; if it does, use View message details instead, which is all the analyser needs.

What you'll see: plain text starting with lines like Received:, Authentication-Results: and ARC-Seal:, followed by From:, To:, Subject: and a long tail of X-MS-Exchange-… lines that Microsoft's servers add for their own bookkeeping. There is no body in this view, only the header section.

Classic Outlook for Windows

1. Double-click the message so it opens in its own window. (Microsoft's steps start this way. In the main Outlook window, the File tab shows account settings instead of the message's properties.)
2. In that window, click File, then Properties (in the Info area).
3. The headers are in the Internet headers box near the bottom of the Properties dialog.
4. Click inside that box, press Ctrl+A to select everything in it, then Ctrl+C.
5. Close the dialog and paste into the analyser.

The box is tiny. It shows four or five lines at a time and can't be resized, so don't try to drag-select through it. Click once inside the box so the cursor is in there, and use Ctrl+A: that selects all the text in the box only, not the rest of the dialog. Microsoft suggests pasting into Notepad if you want to read it; for analysis, paste straight into MailDingo.

The box is empty or nearly empty. That's usually because you opened a message you sent, a draft, or a message that came from another mailbox in the same Exchange organization without crossing the internet. Internal messages can carry very few headers. For outside mail, make sure you're looking at the copy that arrived in your inbox.

Outlook for Mac

Microsoft's header help page doesn't cover Outlook for Mac. Its Outlook for Mac feature list says "view source of received mail" has been available since version 16.58, but we couldn't find an official page giving the menu path. Users report that right-clicking the message in the message list and choosing View Source opens the raw message in a separate window, and in newer builds the item may sit under a View submenu in that right-click menu. Once it's open, click in the text, press Cmd+A, Cmd+C, and paste into the analyser.

If you can't find it, the most reliable fallback is to sign in to Outlook on the web in a browser on the same Mac and use the steps above.

Outlook on iPhone, iPad and Android

Microsoft doesn't document a way to see full headers in the Outlook mobile apps, and its own Message Header Analyzer page says most mobile devices lack a good way to get them. Use a computer if you can, or see the phone guide for workarounds.

Common snags

• "View message details" isn't there. Make sure you're using the … menu at the top of the open message, not the one on the message list or the ribbon.
• Copying grabs only what's visible. In both the message details window and the classic Internet headers box, dragging the mouse only selects what you can see. Use Ctrl+A inside the box.
• Headers look like one enormous line. Some paths lose line breaks when pasted into another program. Paste directly into the analyser, which handles both, rather than through a word processor.
• Your organization added a banner. Many companies insert "External sender" warnings into the body. That changes the body, not the headers, and doesn't affect the analysis.
• Lots of X-MS- lines. They're normal on any message that passed through Microsoft 365 or Outlook.com. The analyser focuses on the standard ones.
• You need to send headers to IT. Many organizations want the message forwarded "as an attachment" so the original stays intact; check your IT team's instructions. An ordinary Forward replaces the original headers with yours.

Next

Paste the headers into the analyser, then use these to read the results:

• Authentication-Results: Microsoft writes compauth= alongside spf=, dkim= and dmarc=; this explains the standard parts.
• Received headers: following the hops back to the sender.
• How to spot phishing from headers and display-name spoofing.