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P7S EML
File conversion

Convert P7S to EML

Verified by Adam B.· reviewed by FE Editorial ·updated Jun 24, 2026
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Is it possible to convert P7S to EML?
Yes - P7S converts to EML.

A .p7s contains no message text - it is the detached cryptographic signature of an email. To get an .eml file, open the original signed message in Thunderbird, Outlook, or Apple Mail; the client processes the .p7s automatically, and you then save the full message as .eml. The .p7s alone cannot be converted.

Also to EML: P7Z · OST · MSG

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Tested on macOS, Windows & Linux
Last verified Oct 2026

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Why convert P7S to EML?

An S/MIME signature (.p7s) carries only the cryptographic signature and the signer's X.509 certificate - not the message body. Opening the original email in an S/MIME-capable client merges the signature with the message into a verified, readable email that can be exported as .eml for archiving, import into another client, or scripted processing.

How to convert P7S to EML

Mozilla Thunderbird OPEN-SOURCE

Open the signed email in Thunderbird - it processes smime.p7s automatically - then right-click the message and choose Save As to export as .eml.

Microsoft Outlook APP

Open the signed email in Outlook; drag the message from the message list to the desktop to create an .eml file, or use File > Save As.

Apple Mail FREE

Open the signed email in Apple Mail - it processes smime.p7s automatically - then choose File > Save As; Apple Mail saves as .eml by default.

About these formats

.P7S PKCS #7 / S/MIME Digital Signature (smime.p7s)

A P7S file - usually named smime.p7s - is the digital signature attached to a signed email. It proves the sender's identity and that the message was not altered in transit. You normally do…

Open .P7S details →
.EML E-Mail Message (RFC 822 / MIME)

An EML file is one email message saved as a plain-text file - headers, body, and any attachments - in the internet-standard MIME/RFC 822 format. You do not need Microsoft Outlook to open…

Open .EML details →

Quality & what to watch

  • The .p7s file alone is useless without the original message it was attached to - both the message body and the signature travel together in the signed email.
  • smime.p7s appearing as a stray attachment is normal behavior in webmail and mobile clients that do not support S/MIME; open the email in Thunderbird or Outlook to process it correctly.
  • The saved .eml includes the original smime.p7s attachment, so the signature data is preserved.

Frequently asked questions

Can I convert the P7S file itself to EML without the original email?
No - a .p7s contains no message content; you need the original signed email open in a mail client.
Does saving as EML remove the digital signature?
No - the .eml file includes the smime.p7s attachment, preserving the signature and signer certificate.
Can webmail export a signed email as EML?
Most webmail clients cannot process S/MIME; download the message to a desktop client like Thunderbird first, then save as .eml.
Is the email content encrypted if it has a P7S file?
No - a .p7s means the message is signed but not encrypted; the email body is readable in plain text.