An alternative to turning off IE is to associate MHT/MHTML with a Chromium browser, Word or even Notepad/Wordpad: How to associate .mht and .mhtml files with a Non-Microsoft Store app

But not Firefox:

Bree said:

Which is great - until you actually want to open an MHT file of your own. Firefox can't, in fact it offers to open it for you in IE.
Apparently Chrome can open .mht/.mhtml files, and now so can the new Chromium-based Edge preview.

Does avoiding the use of IE and not saving web pages or web content avoid the whole issue or should users still either disable IE or associate those files with another program regardless?

Rubi said:

Does avoiding the use of IE and not saving web pages or web content avoid the whole issue

No.

Rubi said:

or should users still either disable IE or associate those files with another program regardless?

Yes.

But the risk is just that if you open a received .htm or .html attachment, they could read a named file which exists in a known folder.

no surprise here with INEPT IGNORER

Wonder how long this flaw has existed with lots of hackers not knowing about it? Well, they know now.

NMI said:

An alternative to turning off IE is to associate MHT/MHTML with a Chromium browser, Word or even Notepad/Wordpad: How to associate .mht and .mhtml files with a Non-Microsoft Store app

This did not work for me, it wanted to associate ALL text files with Chrome. Am I missing something?

Rubi said:

This did not work for me, it wanted to associate ALL text files with Chrome. Am I missing something?

Yes: Create two text files and rename them to test.mht and test.mhtml