Convert RPMSG to PDF

A PDF is useful when a protected Outlook message must be printed, archived, or shared with someone who cannot open rights-managed email. The conversion works only after the recipient authenticates and the message policy permits printing or saving.

What the RPMSG format is

.rpmsg is a rights-managed email container associated with Microsoft Outlook, Exchange, and Microsoft 365 protection technologies such as Microsoft Purview Message Encryption and Azure Rights Management.

Unlike a normal email export, an RPMSG file can keep the message body and attachments encrypted until Outlook or Outlook on the web verifies the recipient’s identity and permissions. Recipients usually encounter it as a protected-message attachment or when opening a protected message outside Outlook.

Without valid authorization, there is no supported conversion method. Renaming .rpmsg to .pdf changes only the filename; it does not decrypt or convert the content.

What the PDF format is

PDF stores a rendered document in a fixed layout that is supported by operating systems, printers, archive systems, and document-management software. It is suitable for a readable, non-editable record of an email, but it is not a native email container.

A printed PDF may not preserve all message headers, conversation structure, signatures, hyperlinks, accessibility information, or attachment relationships. Attachments normally need to be opened and saved separately.

How to convert the message

Outlook for Windows

1. Open the protected message in Outlook and complete any sign-in, verification, or passcode prompt.
2. Check that the message body is fully visible and that you can open any attachments that must be retained.
3. Select File → Print.
4. Choose Microsoft Print to PDF as the printer, set the page range and layout, and select Print.
5. Choose a destination, enter a filename ending in .pdf, and select Save.

Outlook on the web or new Outlook

1. Open the protected message in Outlook on the web or new Outlook and authenticate when prompted.
2. Open the message menu and choose More actions → Print, or select the available print icon.
3. In the browser or system print dialog, select Save to PDF or Microsoft Print to PDF, then save the file.

Microsoft 365 Outlook on the web is the appropriate online option for a protected message because it performs Microsoft identity and rights checks before displaying it. General-purpose online converters, including ordinary document-conversion websites, usually cannot decrypt RPMSG content and should not receive confidential business messages.

If Outlook cannot open the file

Use the protected-message link or attachment in a supported Outlook client or Outlook on the web, and sign in with the account to which the message was granted. If the content still cannot be displayed, ask the sender or Microsoft 365 administrator to provide an authorized alternative; do not upload the file to an unapproved conversion service.

Compatibility and quality limitations

Printing is a visual export, not a decryption workaround. If the rights policy blocks printing, Outlook may disable the command or produce no usable output. A blank or incomplete PDF can also result from failed authentication, an unsupported client, or content that did not finish rendering.

When printing is allowed, the resulting PDF is generally a newly created file and does not automatically preserve the original Microsoft rights-management controls. The organization may separately apply PDF protection, or its policy may prevent creation of the file altogether. Treat a permitted PDF as a potentially shareable copy and handle it according to the message’s confidentiality requirements.

Print the message and save permitted attachments separately when the record must include the original files. If long-term archival compliance is required, check whether the destination system requires PDF/A; Microsoft Print to PDF does not by itself guarantee a PDF/A file.