All about RFC822 Files

The RFC822 file type is primarily associated with Microsoft Exchange Server.

RFC822	File extension: RFC822
	File type:	Text email message file

What is an RFC822 file?

RFC822 files mostly belong to Microsoft Exchange Server.

This RFC822 file is a plain text file that stores an email message. It follows the RFC822 standard, which sets the rules for email headers and the message body.
When you open such a file, you will see important details including:

Headers – Lines that list sender, recipient, subject, and date.
Body – The main text content of the email.
Routing information – Data used by mail systems to process and deliver messages.

FilExt.com tips: This format is used by systems such as Microsoft Exchange Server and by email clients like Mutt. You can open these files with any text editor if you want to inspect the email structure manually. For a more user-friendly view, use an email client that supports RFC822 messages. For further information, visit Microsoft Exchange documentation.

How can I open an RFC822 file?

You need a suitable software like Microsoft Exchange Server to open an RFC822 file. Without proper software you will receive a Windows message "How do you want to open this file?" or "Windows cannot open this file" or a similar Mac/iPhone/Android alert. If you cannot open your RFC822 file correctly, try to right-click or long-press the file. Then click "Open with" and choose an application. You can also display a RFC822 file directly in the browser:. Just drag the file onto this browser window and drop it.

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Programs that open and convert RFC822 files:

Microsoft Exchange Server
See the previous paragraphs to learn more about the main application. RFC822 files are often referred to as Microsoft Exchange Server simple text files because this type of file is primarily created or used by this software.
Email clients (e.g., Thunderbird, Outlook, Apple Mail) and email servers
RFC822 files, often simply called "email files," are plain text files formatted according to the RFC822 standard (later superseded by RFC2822 and subsequently RFC5322). These files store email messages in a structured format that includes headers (like To, From, Subject, and Date) and a body, which can contain plain text or other content encoded according to standards like MIME. The structure allows email clients and servers to parse and process messages reliably. While primarily associated with email, the RFC822 format can also be used for other text-based communication. This file format is classified as Email Message File.

RFC822 file format:

A file format defines how the data in the file is structured. A file format is determined by the file extension and signature, so JPEG images have the extension .jpg and the first bytes in the file are ÿØÿ. Nonetheless, different programs can utilize the same file extension to represent distinct file formats. Double-clicking on the file often results in an error when opening. So you need a detailed analysis of a file to find out the format and the associated program. Our analysis of the RFC822 files produces the following result:

The RFC822 file extension is not widely used. Such a file includes different formats for different programs. But the following two file formats are common:

55% of all RFC822 files start with the bytes Re, which are crucial for this file format. The contents of these files can even be read by a human. The files are on average 150 KB in size and range from 11 KB to 3 MB. The file type is a fairly new file format. The files contain the following words: Received: from, com, PROD, outlook and COM with HTTPS. The file name message-2.rfc822 is typical for these files. These files are often associated with attachment, unnamed and document.
15% of all RFC822 files start with the bytes From: crucial for this file format. These files contain text and words, not binary data. A typical file size is 110 KB. Certain words are almost always found in the files, such as From and Subject. An example of a file name is message-2.rfc822.

All other RFC822 files (30%) have no consistent format, the following 5 formats can be found: Exchange. If you want to find out which format your RFC822 file belongs to, just click on the button "Choose your .rfc822 file to analyze".

Technical Data for RFC822 File Extension

File classification:

Simple text file

Related files:

eml, msg, mbox, emlx, mail, nws, msf, ldif

an rfc822 Text email message file is a special file format and should only be edited and saved with the appropriate software.

How to solve problems with RFC822 files

Associate the RFC822 file extension with the correct application.
Update your software that should actually open text email message files. Because only the current version supports the latest RFC822 file format. Search, therefore, e.g. on the manufacturer website after an available Microsoft Exchange Server update.
To make sure that your RFC822 file is not corrupted or virus-infected, get the file again and scan it with Google's virustotal.com.
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