What is MHT/MHTML File Extension?

MHTML, sometimes referred as MHT, stands for MIME HTML is a single file in which entire webpage is archived. When one saves a webpage as MHTML format, this file extension will contain HTML code, images, audio files, flash animation etc.

  • MHTML (Multipurpose Internet Mail Extension HTML) file format is also known as web page achive format.
  • Not only is the file contains html code for web page but also all the sub-resources (such as images, Java applets, audio files, Flash animation).
  • Internet Explorer and Opera support this file by default
  • In order to save webpage as MHTML file extension in Mozilla Firefox, users need to install an add-on, named Mozilla Archive Format and another one is UnMHT.
  • To archive a webpage as MHT/MHTML in Chrome browser, you need to enter chrome://flags/ in the URL field. Then scroll down, go to Save as MHTML option and select Enable.

The MHT/MHTML file belongs to the category of Web Files.

The following applications create and open MHT/MHTML files.

  • Internet Explorer
  • Opera
  • Google Chrome
  • Firefox
  • Safari
  • ACCESS NetFront
  • GNOME Web
  • Vivaldi
  • MHT viewers
  • multipart/related
  • application/x-mimearchive
  • message/rfc822

hex: 46 72 6F 6D 3A 20 3C

Not a valid MIME document

The error appears when MHT MHTML file format has problem in its structure or format.

Trouble opening MHT files

MHTML files are vulnerable to get infected. The issue occurs when the file is not scanned before opening it.