Classic Outlook EML Files in New Outlook: What Changed

You may have used EML files in classic Outlook to save individual emails as separate files for archiving, sharing, or importing. In the new Outlook for Windows, the way these files are handled has changed significantly. The new app no longer supports direct opening or saving of EML files as a native feature. This article explains exactly what changed, why it matters, and how to work with EML files in the new Outlook.

How Classic Outlook Handled EML Files

In classic Outlook (Microsoft 365, Outlook 2019, 2021, and earlier), EML files are treated as native email messages. You can open an EML file by double-clicking it, and it displays the full email including headers, attachments, and formatting. Classic Outlook also supports saving any email as an EML file through the Save As dialog. The file format uses the MIME standard, which means it preserves the original structure of the email, including embedded images and attachments. Classic Outlook also allows you to import multiple EML files at once using the Import and Export wizard (File > Open & Export > Import/Export > Import from another program or file). This made EML files a common tool for archiving individual messages, sharing email evidence, or migrating data between email clients.

What Changed in New Outlook for Windows

New Outlook for Windows is a complete rebuild of the email client based on the web version of Outlook. It uses a different underlying engine that does not include direct support for the EML file format. This change affects three key operations:

Opening EML Files

Double-clicking an EML file in Windows will no longer open it in new Outlook. Instead, the file may open in a web browser or prompt you to choose a different program. New Outlook does not register itself as a handler for the .eml file extension. If you have both classic and new Outlook installed, classic Outlook will still open EML files by default unless you change the file association manually.

Saving Emails as EML Files

The Save As dialog in new Outlook no longer offers the EML file format. The only available formats are MSG (Outlook message format) and OFT (Outlook template). To save an email as an EML file, you must use classic Outlook or a third-party conversion tool.

Importing Multiple EML Files

New Outlook does not include an Import/Export wizard. You cannot import a folder of EML files directly. The only way to bring EML content into new Outlook is to open each file individually in classic Outlook or a compatible email client, then drag or forward the message to your new Outlook mailbox.

How to Open an EML File in New Outlook

Although new Outlook does not natively support EML files, there is a workaround using drag-and-drop. This method only works if the EML file is already associated with an email program on your system, such as classic Outlook or Windows Mail.

1. Open File Explorer
   Navigate to the folder containing the EML file you want to open.
2. Drag the EML file into the new Outlook window
   Click and hold the EML file, then drag it over the new Outlook window. Release the mouse button when the window highlights. The email content appears as a new message in the Drafts folder or the active mailbox.
3. Review and send or save the message
   The dragged email may lose some formatting or attachments. Check the content and attachments before sending or moving it to another folder.

If the drag-and-drop method does not work, open the EML file in classic Outlook first. From classic Outlook, forward the message to your new Outlook email address, or use the Move to option to copy it to a shared mailbox that both clients can access.

How to Save an Email as an EML File from New Outlook

New Outlook does not provide a direct way to save an email as an EML file. To achieve this, use one of the following methods:

1. Use classic Outlook to save the email as EML
   Open the email in classic Outlook. Go to File > Save As. In the Save As dialog, choose the location and set the Save as type to EML file. Click Save.
2. Forward the email to a classic Outlook account
   Forward the email from new Outlook to an email account that you access with classic Outlook. Open the forwarded message in classic Outlook, then save it as an EML file.
3. Use a third-party conversion tool
   Several free and paid tools can convert MSG files (which new Outlook can save) to EML format. Save the email as an MSG file in new Outlook (File > Save As > Outlook Message Format), then use a converter like CoolUtils MSG to EML or a PowerShell script to change the format.

Common Issues When Working with EML Files in New Outlook

EML file opens in a web browser instead of Outlook

This happens because new Outlook does not register as the default handler for .eml files. To change the file association, right-click any EML file, select Open with > Choose another app, and select classic Outlook or another email client. Check the box Always use this app to open .eml files. If classic Outlook is not listed, click More apps and browse to the Outlook.exe file (usually in C:\Program Files\Microsoft Office\root\Office16).

Drag-and-drop creates a blank or corrupted message

If the EML file contains complex formatting, embedded images, or non-standard headers, the drag-and-drop method may fail. Open the file in classic Outlook first, then copy the content manually. Alternatively, use a dedicated EML viewer to extract the text and attachments, then compose a new message in new Outlook.

Cannot import a batch of EML files at once

New Outlook lacks bulk import for EML files. To migrate a large number of EML files, use classic Outlook’s Import and Export wizard: File > Open & Export > Import/Export > Import from another program or file > Comma Separated Values (this does not directly support EML). A better approach is to open each EML file in classic Outlook and move it to a PST file, then import the PST file into new Outlook. However, new Outlook does not support PST files either. The most reliable method is to use a third-party migration tool that converts EML files to the format used by new Outlook (which stores data in the cloud or in an OST file).

Classic Outlook vs New Outlook: EML File Support Comparison

Item	Classic Outlook	New Outlook
Open EML file by double-click	Yes, opens as a message	No, file opens in browser or other app
Save email as EML	Yes, via File > Save As	No, only MSG and OFT formats available
Drag-and-drop EML into mailbox	Yes, imports as a new message	Limited, may lose formatting
Bulk import of EML files	Yes, via Import/Export wizard	No, no import wizard exists
EML file association	Registered by default	Not registered
Attachment handling in EML	Preserved fully	May be lost during drag-and-drop

The table shows that classic Outlook remains the only fully compatible client for EML files within the Microsoft ecosystem. If you rely on EML files for archiving or sharing, continue using classic Outlook or switch to a third-party email client that supports EML natively, such as Mozilla Thunderbird or eM Client.

You can now decide whether to use the drag-and-drop workaround, switch back to classic Outlook, or adopt a third-party tool for EML file handling in new Outlook. For users who frequently work with EML files, the most reliable solution is to keep classic Outlook installed alongside new Outlook. Use classic Outlook for all EML-related tasks and new Outlook for daily email management. As a next step, review your file associations in Windows Settings to ensure EML files open with classic Outlook by default. A concrete tip: if you need to send an EML file as an attachment from new Outlook, save the email as MSG first, then attach it to a new message — the recipient can open the MSG file in classic Outlook.