So you have a Windows Mail .eml file? What is it, and how can you make sense of it?
It is quite common to encounter .eml files as email attachments. To understand them, let's consider how a .eml file may come to exist. If you are a Windows Live Mail user, you may find that the process to save a e-mail message as a .eml file is quite simple. Knowing how this is done makes it easy to share messages with someone without having to forward the message. Sometimes the context of the email message is best preserved when the message is shared in its entirety as a separate file. EML files can simply be included in an email message as a file attachments, while a forwarded message is more susceptible to manipulation.
To create a .eml file using Windows Live Mail, start by going to the program's main menu. Second, single click on any email displayed in the message list (don't open it, just highlight it). Third, click the the far left button in the tool ribbon, choose "Save as File," and the select a location to save the file. Your message will be saved as a .eml file.
|Saving a Windows Mail message as .eml (1)|
|In Windows Mail, save the message as a .eml file|
Another way to create a .eml file from Windows Live Mail is to just drag it out of the inbox and drop it on your desktop. That works, too.
What is a .EML file?
If you want to get technical about it, a file with a .eml extension should conform to RFC-2822, the internet message format. This standard establishes a common syntax for text messages so they can be sent between computer users as e-mail. Each .eml file contains a single email message (unless of course another .eml file is embedded inside of the .eml file, but each .eml file is really a separate instance of an email message).
Most .EML files you will encounter are created by popular email clients such as Microsoft Outlook Express, Windows Live Mail, or Mozilla Thunderbird. To create a .eml file using either of those two email clients, all you have to do is drag an email message from the inbox and drop it on your desktop. Voila! Instant .eml file which will contain a header in plain ASCII text, the main body of the message (text or html), and any file attachments associated with the email, such as spreadsheets, jpg pictures, videos, or text documents.
.EML files can range in size from 1 kilobyte to many megabytes, depending of course on what the sender has chosen to put into the file.
The truth is, not all .eml files conform exactly to RFC-2822. In the wild, you are likely to encounter many exceptions. Different software products that generate .eml files sometimes fail to implement the entire RFC standard. When this happens, emails may not be formatted correctly, or are unable to be opened. PstViewer Pro is a .eml viewer software application that has identified dozens of these exceptions, and is therefore able to render many non-standard .eml files.
Often many email messages are grouped into larger files, such as a .PST file (Outlook) or a MBOX file (Thunderbird). While Thunderbird and Windows Mail will allow you to save a single message as a .eml file, Microsoft Outlook does not allow this. Rather, Outlook saves individual emails as a .msg file, which is a Microsoft Office message format that is not RFC-2822 compatible. As of Outlook 2010, Microsoft Outlook does not save email messages as .eml files. MessageExport is a third party add-in for Microsoft Outlook that adds this ability to Outlook, allowing Outlook emails to be stored in EML format.