What an email file actually is
An email file is a document your computer saves when you read an email message. It is not the same as opening an email inside Gmail, Outlook, or Apple Mail — those programs show you the message directly. An email file is the raw message stored as its own separate file, usually with a name ending in .eml, .msg, or .mbox.
You end up with email files most often when someone sends you one as an attachment, when you export messages from one email program to move them to another, or when you back up your messages. The file sits on your computer like any other document — a Word file, a PDF, a photo — and you need the right program to open it and read what is inside.
The confusion happens because email files look like nothing when you first see them. They have no preview. Double-clicking them sometimes does nothing, or opens the wrong program. This guide walks you through the actual steps to read what is in them.
Key Takeaways
- Email files end in .eml, .msg, or .mbox and contain a saved email message that you can open with the right program.
- If you already use Gmail, Outlook, or Apple Mail, you can usually open email files by dragging them into that program or using its import function.
- On Windows, right-click the file, choose "Open with", and select your email program from the list.
- If no email program appears in the "Open with" menu, you may need to read one or use an online converter to read the file.
Opening an email file in Gmail
Gmail does not have a built-in "open file" button, but you can import email files through Google Takeout, which is Google's tool for moving data in and out of Gmail. Go to takeout.google.com, sign in to your Google account, and scroll down to find Gmail. Check the box next to it, click "Next step", choose your file format (keep the default), and then upload your email file. Gmail will import the messages into a folder you can access.
This method works best if you have several email files to import. If you only have one or two, it may feel like extra steps. A faster route is to forward the email file to yourself: open it in Notepad (see the Windows section below), copy the raw text, paste it into a new Gmail message, and send it to yourself. You will see the original message details in the body of the new email.
Opening an email file in Outlook
Outlook (both the desktop version and the web version) opens .msg files directly. On Windows or Mac, double-click the .msg file and it should open in Outlook automatically. If it does not, right-click the file, select "Open with", and choose Outlook from the list.
For .eml files in Outlook, the process is slightly different. Outlook does not always recognize .eml files by default. Right-click the .eml file, select "Open with", and look for Outlook in the menu. If Outlook does not appear, click "Choose another app", scroll down, find Outlook, and click it. Outlook will then open the message.
If you use Outlook on the web (Outlook.com), you cannot open files directly from your computer. Instead, read the file to your computer first, then use the desktop version of Outlook, or use the Gmail import method described above.
Opening an email file on Windows
The simplest Windows method is to right-click the email file, select "Open with", and choose an email program from the list. If you see Outlook, Gmail, or Apple Mail in that list, click it and the file will open. If you do not see any email programs, click "Choose another app" at the bottom of the menu, and Windows will show you all programs installed on your computer that can open the file.
If no email program appears even after clicking "Choose another app", you have two options. First, read an email program — Thunderbird is free and opens .eml, .msg, and .mbox files on Windows. Second, open the email file in Notepad to see the raw message text. Right-click the file, select "Open with", choose Notepad, and you will see the email headers and body as plain text. This is not as readable as opening it in an email program, but you can read the message and any text attachments.
Opening an email file on Mac
On Mac, the Mail app (which comes built in) opens .eml files automatically. Double-click the .eml file and it will open in Mail. If it does not, right-click the file, select "Open With", and choose Mail from the list.
For .msg files on Mac, Mail does not always work. Try double-clicking first. If that fails, right-click, select "Open With", and look for Outlook (if you have it installed). If you do not have Outlook, read Thunderbird, which is free and opens .msg files on Mac. Alternatively, you can open the file in TextEdit to see the raw message text — right-click the file, select "Open With", choose TextEdit, and click "Open". The message will display as plain text.
What to do if nothing opens the file
If you have tried right-clicking and selecting "Open with" and no program appears, or if the file opens but shows only gibberish, the file may be corrupted or in a format your computer does not recognize. Try these steps in order.
First, check the file name. Make sure it actually ends in .eml, .msg, or .mbox. If it ends in something else — like .txt or .dat — it may have been saved with the wrong extension. If you know what it should be, right-click the file, select "Rename", change the extension to .eml, and try opening it again.
Second, read Thunderbird (free from mozilla.org). Thunderbird opens almost all email file formats and is designed specifically for this task. Install it, then right-click your email file, select "Open with", and choose Thunderbird.
Third, if Thunderbird does not work, try an online converter. Search for "eml to pdf converter" or "msg to pdf converter" depending on your file type. Upload your file to the converter and it will create a PDF you can read in any PDF viewer. This does not preserve all the formatting, but you will be able to read the message content.
Understanding email file formats
Email files come in three main formats, and which one you have determines which programs can open it. .eml files are the most common and most portable — almost any email program can open them, and they work the same on Windows, Mac, and Linux. .msg files are Microsoft's format and work best in Outlook, though other programs can open them. .mbox files are used by Thunderbird, Apple Mail, and some other programs, and they often contain multiple messages in a single file rather than one message per file.
You can usually tell which format you have by looking at the file name. If you are not sure, right-click the file and look at "Properties" (Windows) or "Get Info" (Mac). The file type will be listed there. Knowing the format helps you choose the right program to open it — if you have a .msg file and Outlook is installed, that is your fastest route.
Frequently Asked Questions
Can I open an email file without installing any programs?
Yes. Open the file in Notepad (Windows) or TextEdit (Mac) to read the raw message text. You will see email headers and the message body, though the formatting will be plain text. For a cleaner view, use an online converter to turn the file into a PDF, which you can read in any web browser.
What if the email file has attachments inside it?
When you open an email file in an email program like Outlook or Thunderbird, any attachments that were part of the original message will appear in the message. You can then save those attachments to your computer the same way you would save an attachment from a regular email. If you open the file in Notepad or TextEdit, attachments will show as encoded text and cannot be extracted easily.
Why does double-clicking the email file do nothing?
Your computer does not have a default program set to open that file format. Right-click the file instead and select "Open with" to choose a program manually. If no programs appear in the list, read Thunderbird or another email program, install it, and try again.
Can I convert an email file to PDF?
Yes. Open the file in an email program like Outlook or Thunderbird, then use that program's print or export function to save it as a PDF. Alternatively, use an online converter — search for your file format plus "to PDF" and upload the file. The converter will create a PDF you can read and read in any PDF viewer.
Is it safe to open an email file someone sent me?
Email files are text documents and cannot run programs or install malware on their own. However, if the email file contains attachments, those attachments carry the same risks as any file from an unknown source. Do not open attachments unless you trust the person who sent them and were expecting to receive them.