Export a test email from Apple Mail as raw message source
Mail on Mac can save a single message as .eml. Select the original source format so the saved file contains the received message rather than a formatted copy.
Save one message
- Select the received campaign test.
Select the individual message in Mail. A conversation can contain several messages; check that you are saving the one you intend to inspect.
- Choose File, then Save As.
Pick a folder and a filename you can recognize later.
- Select Raw Message Source.
Apple documents this format as saving a single message in
.emlformat. Rich Text, Plain Text and PDF are different exports. - Check the result.
The file must be
.emland no larger than 2 MiB (2,097,152 bytes) for SendProofs.
Apple also documents dragging a message to the desktop to save it as .eml. Dragging a conversation can produce separate files for its messages. For one campaign check, choose the intended received test.
When the export is different
You saved Rich Text or PDF
Return to the original message and export Raw Message Source. Changing the filename extension does not convert another format into a MIME message.
The extension is hidden
Check the file's information in Finder before uploading. A filename alone is insufficient evidence of its format. If the source export did not produce .eml, repeat the documented export instead of guessing.
Your test is on iPhone or iPad
The documented steps here are for Mac. Use a computer with access to the same mailbox and an export route your organization permits. Our Gmail and Outlook guides cover their computer interfaces.
The saved message is too large
SendProofs rejects files above its limit. Reduce unnecessary embedded material in the sending platform and send yourself a fresh test, then export that message. Do not remove parts from the saved source and assume it still represents the delivered campaign.
Documentation and next step
These instructions were checked against Apple's Mail on Mac guide, Save emails as files or PDFs section on 19 October 2026. Apple now includes that section in its storage guide. This is a documentation check, not a test of your Mac or mailbox.
Upload only a test you are authorized to process. Read data handling for the fields retained in a report, then follow upload help. Keep campaign files out of support emails.