open mht in firefox quantum - unable to open the file in new browser version
I was using list of links created in mht file format and use them in multiple browsers. It used to work fine with older firefox browser versions with UnMHT addon. But the new addon is not compatible with Quantum, nor the browser supports it.
I am not able to use the browser because of this.
Wšě wotmołwy (3)
If you cannot be productive without UnMHT, you may need to temporarily roll back to Firefox 56 until you can export your MHT file to a standard format (e.g., Save Page As, Web page complete or if you don't need images or other external files, HTML only).
See: Install an older version of Firefox
Alternately, you could use Internet Explorer or another browser that reads .mht files to save it to a standard format that you then can open in Firefox.
MHTML format isn't an "official standard" in W3C standards. It remains "proposed" since 1999. Mozilla doesn't support "proposed standards". https://en.wikipedia.org/wiki/MHTML
IMO, there is a slight bit of incompatibility between the format that UnMHT saves to with how IE handles those files. So for me IE is a no-go.
My "solution" is to have an older version of Portable Firefox installed with the UnMHT extension so I can read the hundreds of MHT files that I saved over the last 12 years.
I think what is needed is summed up here: