.RPMSG File Extension

An RPMSG file is a protected email message file created by Microsoft Outlook, Microsoft's email and calendar application. It contains an email that has been encrypted such that only certain users can view, print, copy, or forward the email. RPMSG files are sent as attachments to standard email messages; these attachments use the filename message.rpmsg.

In Microsoft Outlook and other email applications, you can open a protected email message by clicking the message.rpmsg file attached to an email. When using an application other than Outlook, you may be redirected to a separate webpage to view the protected message.

NOTE: Keep in mind that you can open a protected message only while logged in to an email account that the message was originally sent to.