Files with the file extension MSG are mail documents that are associated with Microsoft Exchange which is a collaborative email messaging server used by many businesses and organizations. The Exchange server supports IMAP, POP, and web mail clients which are commonly used with Microsoft Outlook. MSG files are designed to work with all Microsoft infrastructure solutions and identify mail messages which were created using Outlook Express or Microsoft Outlook.
Similar to other Microsoft programs such as Word and Excel, MSG files are saved as Component Object Model storage documents that are comprised of OLE (Object Linking and Embedding) which allows the documents to be linked with other objects. There are several streams included in an MSG file, each of which contains a subtag with an 8-digit code. By reading the first four digits you can identify the document nameid, attachment, content in the body of the message, and the sender. The second set of digits describes the encoding which was used to create the MSG file such as binary or ASCII text.
In terms of content, MSG files can contain calendars, contacts, messages, reminders, and other components typically used with messaging programs. The files can also support mobile and web-based access to information and are organized in a hierarchal structure.
How to Open MSG Files
MSG files are compatible with programs that use the Microsoft Messaging Applications Programming Interface used with the Exchange server. Therefore, if you use the Windows operating system, you can open MSG files with the Microsoft Outlook email client. Other compatible programs for opening and viewing MSG files in Windows include the EX Freeware Free Opener and Encryptomatic MsgViewer Pro which allows you to view, convert, and manage email content that is stored in an MSG file. The program allows you to search your email account and then work with the email messages using your email client. You can also convert MSG files to another format such as PDF, text, or an image format to make them easily readable by other programs.
If you are using Mac OS X, you can open and view MSG files using Kupon.BG Klammer, which is also compatible with Linux. You can also use 45RPM MailRaider for Mac OS X to open and read MSG files, extract the attachments and convert the content to RTF (Rich Text Format) for easy accessibility. If you are using Version 0.7.0, this lends support for OS X 10.7 Lion and is only available as Intel.
There is also a variety of freeware programs you can download from sites such as Softpedia and CNET. They will convert MSG files to a format that is readable by other software applications that do not rely on the Messaging Applications Programming Interface.