EML is a file format designed for Outlook and Outlook Express, developed by Microsoft. This file type is used for storing emails while preserving the original subject and HTML formatting. While most email clients support EML files, if you don’t have an email client installed or you're using a mobile device, there are still ways to open this type of file.
Steps
Troubleshooting

EML file won't open in Outlook Express after installation. Typically, this happens because another program has taken control of the EML extension. You will need to reset the file associations for Outlook Express.
- Close Outlook Express if it's open.
- Press ⊞ Win+R.
- Enter msimn /reg and press ↵ Enter. This will reset the file association for Outlook Express. From now on, EML files will automatically open in Express with a simple double-click.

Check the file extension. Some users have reported that backups created by Windows Live Mail altered the EML file extension from *._eml to *.eml. If you can't open the EML file, check whether the extension has been changed.
- Refer to step 2 in this section to enable file extensions if they are hidden.
- Rename EML files with the *._eml extension by removing the _ character.
On Windows

Open the EML file using a mail client. EML files are essentially emails stored in a file format. The easiest way to open an EML file is to use a mail client like Outlook, Outlook Express, Windows Live Mail, or Thunderbird. Most recent versions of these programs automatically support EML files, allowing you to simply double-click the file to open it.
- When opening an EML file in a mail client, you can download any attachments and view both the formatting and images properly.
- If you don’t have a mail client or can't open the EML file in one, continue reading below.

Change the file extension to view it in a web browser. EML files have similarities to MHTML files, and changing the extension to *.mht quickly converts the file into a format that can be opened in Internet Explorer. Although other web browsers can open MHT files, Internet Explorer is the only browser that displays the format correctly. However, this method does not allow you to download attachments.
- Enable file extensions if they are hidden. In Windows 8, check the "File name extensions" box under the View tab in File Explorer. For older versions of Windows, open the Control Panel, select Folder Options, go to the View tab, and uncheck "Hide extensions for known file types".
- Right-click on the EML file and select "Rename".
- Delete the .eml extension and replace it with .mht. Windows will warn that this could cause issues with the file, but you can proceed with the extension change.
- Open the file in Internet Explorer. This is the default program for MHT files. You can right-click the file, select "Open with", and choose Internet Explorer from the list. Internet Explorer will display the MHT file in a format similar to how it would appear in a mail client.

Download and install FreeViewer EML File Viewer. You can download the free program here: http://www.freeviewer.org/eml/.
- Go to the folder containing the EML file.
- Double-click the folder. The EML files will be listed in order. Now you can click on any EML file to view its contents.
- You can also view any attachments included with the email.

View the file as plain text. If you are unable to open the file in your mail browser or convert it to view in Internet Explorer, you can view the file in plain text format. The text may contain some strange characters, but you'll still be able to read the main content along with any links. However, images and attachments won't be visible.
- Right-click on the EML file and select "Open with".
- Choose Notepad from the program list.
- Look for the <html> and <body> tags. These mark the beginning of the email content, which you can read here, although you may need to remove some HTML code.
- Look for the <a href= tag to view the links. You can copy and paste the displayed URL into a web browser to access the mentioned links in the EML file.
On Mac

Open the EML file in Apple Mail. This program comes pre-installed on OS X and allows you to fully view the EML file's content.
- Right-click (or press Ctrl and click) on the EML file and select "Open With...".
- Choose "Mail" from the program list. The EML file will open in Apple Mail, even if you haven't set up an email account in the program.

Use Microsoft Entourage or Outlook for Macintosh. If you have Office 2008 or 2011, you can install the Microsoft email client to open the EML file. Office 2008 includes Entourage, while Office 2011 replaces it with Outlook for Macintosh. You may have skipped installing the mail client during the Office software setup.
- After installation, right-click (or press Ctrl and click) the EML file and select "Open With...". Choose Entourage or Outlook from the displayed program list.

Extract the file using StuffIt Expander. This free extraction tool for OS X can be used to extract the information from the EML file.
- Download and install StuffIt Expander from my.smithmicro.com/stuffit-expander-mac.html or from the Mac App Store.
- Drag the EML file into the StuffIt window. You can extract multiple EML files simultaneously by dragging all the files into the window at once.
- Open the newly created folder for each EML file. You will find the attachments and images saved as separate files, alongside a text file containing the email's content.

View EML file as plain text. If you don't have an email client and can't install Stufflt Expander, you can open the EML file in TextEdit. This method will allow you to view the content and links of the email. However, images and attachments won't be visible.
- Right-click (or press Ctrl and click) on the EML file and choose "Open With...".
- Select "TextEdit" from the list of applications. You may need to browse for this program.
- Look for the HTML tag <body>. This helps identify the content section of the email. Links will appear with the <a href= tag.
On an iPad

Download and install the Klammer app. This app is available on the App Store for $0.99 (about 23,000 VND). It will allow you to open and view the content of EML files. Currently, this is the only method to view an EML file without converting it on another platform first.

Open the Mail app (or any app that contains the EML file you want to open). You can use Klammer to open the EML file attached to an email, stored in Dropbox, or any other cloud storage service, or any other program that supports the file format.
- If using Mail, tap on the attachment to download the content to your iPad. You also need to download the file to your iPad when using Dropbox or Google Drive.
- If you're unable to download the attachment, try forwarding the email to yourself and downloading it again.

Tap the downloaded file. You will be prompted to choose an app to open the file with.

Tap "Open in Klammer". The EML file will be downloaded to the Klammer app, and the content will be displayed in its proper format.
On Android

Download the EML Reader FREE app. By default, Android doesn't support the EML format. The only way to open an EML file on an Android device is by installing an additional app.
- The EML Reader FREE app is the most recommended option among available EML readers, though you can choose other apps if you prefer. Simply search for "eml reader" in the Google Play Store.

Open the EML file. How you open the EML file depends on how you received it.
- If you received the EML file as an attachment, open the email containing the attachment in Gmail or Mail and tap on the EML file.
- If you downloaded the EML file from a website, use the File Manager app to navigate to the Download folder, or open the EML Reader FREE app to view the file.

Select EML Reader FREE from the list of apps. When opening the EML file, you will be prompted to choose an app. The EML Reader FREE app will appear in the list. Choose "Always" to set this app as the default for opening EML files.

View the EML file. The EML Reader FREE app divides the EML file into different sections, including From/To (Sender/Recipient), Date, Subject, Text, HTML, and Attachments.
- The "Text" section contains the body content of the EML file.
- The "HTML" section displays the email in its original HTML format.

Press and hold an attachment to open it. A list of attachments will appear at the bottom of the display. This includes all images used in the HTML email and any files attached to the email.
- When you press and hold an attachment, a new menu will appear. Select "Open" to choose an app that can read this type of file. Alternatively, you can select "Save" to extract the file from the EML and save it in the same folder.
