Windows
Compatible applications
Quick Facts
Basic information about this file format
Extension
.EML
File Type
Electronic Mail Format
Category
Data
Best first step
Use compatible software
Quick Summary
A practical overview of the .eml file format
An EML file is a standard file format used to store individual email messages. It was originally developed by Microsoft for Outlook Express but has since evolved into a universal standard (RFC 822 and RFC 5322) supported by the vast majority of email clients and servers. The file structure consists…
File extension
.EML
File type
Electronic Mail Format
Category
Data
Recommended action
Open with a trusted compatible app
How to open a .eml file
Start with a trusted app that supports this format
- Check the file extension carefully and confirm that the file name really ends with .eml.
- Use software that supports this file type. If one app does not work, try another compatible program for the same platform.
- Update the application if the file was created by a newer version of the software.
- Scan files from unknown sources before opening them, especially documents, archives, scripts, installers, and executable files.
What is a .eml file?
File extension details and usage information
An EML file is a standard file format used to store individual email messages. It was originally developed by Microsoft for Outlook Express but has since evolved into a universal standard (RFC 822 and RFC 5322) supported by the vast majority of email clients and servers. The file structure consists of plain text that includes the original email headers—such as the sender, recipient, date, and subject line—followed by the message body. EML files are capable of storing complex content including HTML formatting and file attachments, which are typically encoded using Base64 to ensure they can be transmitted as text. Because the format is essentially a text-based structure, EML files can be opened and read by basic text editors like Notepad or TextEdit, though they are best viewed in dedicated email software to render formatting and access attachments correctly. They are widely used for archiving individual messages, legal discovery, and migrating emails between different software platforms due to their high level of compatibility and standardized nature.
Software Compatibility
Programs that may open or work with .eml files
macOS
Compatible applications
Linux
Compatible applications
Mobile
Mobile applications
Can .eml files be converted?
Options for saving or exporting this file to another format
In many cases, a .eml file can be converted by opening it in compatible software and using an option such as Save As, Export, or Convert. The available output formats depend on the file type and the application used.
- Use the original software that created the file when possible.
- Check whether the application supports exporting to common formats.
- Be careful with online converters when working with private, business, or sensitive files.
- If conversion fails, the file may be corrupted, incomplete, encrypted, or not actually a .eml file.
Why can't I open a .eml file?
Common reasons this file type may not open correctly
Wrong software
The file may require a specific program that supports the .eml format.
Incorrect extension
The file extension may have been renamed manually, even though the actual file format is different.
Corrupted file
The file may be incomplete, damaged during download, or transferred incorrectly.
Outdated app
Your software may need to be updated before it can open newer versions of this file format.
Frequently Asked Questions
Common questions about .eml files
To open a .eml file, use software that supports this file format.
- Microsoft Outlook
- Mozilla Thunderbird
- Windows Mail
- Notepad
- Apple Mail
Open the file in compatible software and look for options such as Save As, Export, or Convert. If no export option is available, the file may require a specialized converter or the original application that created it.
- Verify that the file extension is correct.
- Install or update compatible software.
- Try another application that supports this format.
- Check whether the file is corrupted, incomplete, or encrypted.
A file extension alone does not guarantee whether a file is safe or unsafe. Only open files from trusted sources, scan unknown files before opening them, and be especially careful with executable, script, archive, and document files.
File safety tips
Use caution with unknown files
Only open files from trusted sources. Before opening a .eml file, scan it with antivirus software, verify that the file extension is expected, and avoid running unknown executable, installer, macro-enabled document, or script files.