.MHT file extension
To open .MHT files on Windows, right-click the .mht file and choose Open with → Google Chrome or Microsoft Edge.
To open a .mht file, try opening it in a web browser such as Google Chrome or Microsoft Edge. If it doesn’t open correctly, the file may be blocked by browser security settings or may not be a valid MHTML archive.
Last updated: June 12, 2026
Open on your device
Choose your operating system for a dedicated step-by-step opening guide.
How to open .MHT files
Use these platform-specific instructions to open .MHT files safely.
Windows
- Right-click the .mht file and choose Open with → Google Chrome or Microsoft Edge.
- If it opens in the wrong app, choose “Choose another app” and select your browser, optionally setting it as the default for .mht files.
Mac
- Try opening the .mht file with a browser that supports MHTML on your Mac (support varies by browser/version).
- If it won’t open in your installed browsers, transfer the file to a Windows PC and open it with Microsoft Edge or Google Chrome.
Linux
- Try opening the .mht file in a browser that supports MHTML on your system (support varies by browser/distribution).
- If your desktop environment doesn’t recognize the file type, update the shared-mime-info database or open the file from within a browser via its File → Open menu.
iOS
- If it doesn’t open in your available apps, transfer the .mht file to a desktop browser (commonly Chrome/Edge) to view it.
Android
- Try opening the .mht file in a browser that supports MHTML on your device; if it fails to render, move the file to a desktop browser (commonly Chrome/Edge).
Security notes
- An .mht file can contain HTML and potentially active web content (scripts, links, and embedded resources). Treat it like a web page: opening a malicious archive can expose you to phishing UI, tracking links, or content designed to exploit browser vulnerabilities.
- MHTML is a multipart/related MIME container (RFC 2557 / RFC 2387). Tools that parse MIME parts may be exposed to malformed structure edge cases; prefer opening in a fully updated browser with modern security sandboxing.
- Be cautious with .mht files received via email or downloaded from unknown sources; the format resembles MIME messages and may be used to disguise harmful content inside an apparently “single file” web page.
If you did not expect this file
This extension is usually plain data, text, or structured content—not a program by itself. The practical risk is social engineering (a scam attachment or misleading filename). For trusted senders you rarely need heavy-handed antivirus wording; use these tools when you want an extra check on unexpected downloads.
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Can't open this file?
These are the most common causes and fixes when .MHT files fail to open.
Common reasons
- The file opens as plain text or downloads instead of displaying as a page
- Images or styling are missing when viewing the archive
- The browser refuses to open the file or blocks active content
Fix steps
- Open the file explicitly with a web browser known to support MHTML (for example, Google Chrome or Microsoft Edge).
- If your browser still shows text, the file may not be valid MHTML; confirm the file really has multipart/related content and wasn’t renamed incorrectly.
OS-specific troubleshooting
What is a .MHT file?
MHTML (often saved as .mht) is a MIME-encoded “aggregate document” format that bundles an HTML root document together with its linked resources into one file. Technically, it is typically structured as a MIME message using multipart/related, where one part is the main HTML and other parts contain images, stylesheets, etc. The MHTML encapsulation approach is described in RFC 2557 and relies on multipart/related as specified in RFC 2387.
Background
An .mht file is essentially a self-contained snapshot of a web page. Instead of storing an .html file plus a folder full of images and other assets, MHTML packages the page and its dependencies into a single MIME-formatted file, which makes it convenient for sharing or archiving a page as it appeared at a point in time.
Under the hood, MHTML uses MIME mechanisms similar to email messages: a multipart/related container holds the “root” HTML document and the related parts (such as images). This makes it interoperable with software that understands MIME multipart structures, and it is standardized around the idea of encapsulating an aggregate document.
In day-to-day use, people encounter .mht files when saving web pages for offline viewing or when exporting “single file” web archives. Common viewing is done directly in a web browser that supports MHTML rendering.
Common MIME types: multipart/related, message/rfc822
Known aliases: .mhtml
Further reading
Authoritative resources for more details on the .MHT format.
Common .MHT issues
The file opens as plain text or downloads instead of displaying as a page
Some apps don’t recognize MHTML packaging and treat .mht as a generic text or message-like file, so you see MIME boundaries and encoded parts instead of a rendered web page.
- Open the file explicitly with a web browser known to support MHTML (for example, Google Chrome or Microsoft Edge).
- If your browser still shows text, the file may not be valid MHTML; confirm the file really has multipart/related content and wasn’t renamed incorrectly.
Images or styling are missing when viewing the archive
If the archive was saved incorrectly, not all linked resources were embedded as related parts, so the HTML references assets that are not present inside the MHTML file.
- Re-save the page as MHTML from the original source (if available) and ensure the save option is for a single-file web archive.
- Try a different MHTML-capable browser; parsing can differ between implementations.
The browser refuses to open the file or blocks active content
Because an MHTML file can contain active web content, browsers may apply restrictions when opening local archives, especially if the file came from the internet or email.
- If you trust the source, copy the file to a local folder you control and open it from the browser’s File → Open menu.
- If it’s from an untrusted source, do not bypass warnings; request the content in a safer format (e.g., PDF) or view it in an isolated environment.
FAQ
What is the difference between .mht and .html?
.html is usually just the HTML markup, while .mht (MHTML) packages the HTML together with related resources (like images and CSS) into a single MIME multipart/related file.
Why do I see weird boundaries and encoded text inside the file?
That’s the raw MHTML/MIME structure. Open the .mht in an MHTML-capable web browser to render it as a page instead of viewing it in a text editor.
Is .mht standardized?
MHTML encapsulation is specified in RFC 2557 and commonly uses multipart/related as defined in RFC 2387.
Which programs commonly open .mht files?
Web browsers are the most common viewers; references commonly list Google Chrome and Microsoft Edge among supported browsers.
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