How to get Windows 10 to use Firefox instead of Edge

I know how to set Firefox as my default browser within the Firefox settings. I also have Firefox set as my default browser in Windows 10 settings.

However, I still get a lot of things that open up in Edge or Internet Explorer; let’s say during an app install when it opens the home web site, etc.

I went into Windows 10 settings and searched by app for associations. I see that a lot of file types, such as .mht, .xht, etc. are set to open with Internet Explorer. But the only options to change this are Internet Explorer and “Look for an App in the store” which doesn’t of course give me a Firefox option.

How can I set up Windows 10 so it always opens Firefox and never uses Edge or IE?

It almost seems like something has gone wrong with the Firefox installation if its not appearing as an option when you change file types associations because it should have registered itself as an app. Maybe try uninstalling and reinstalling it. Back up your bookmarks etc first though.

If I click on, say, .htm or .html, it shows Firefox (as I would expect setting Firefox as my default browser in Windows 10 settings.) It also shows it as an app option for those.

But other protocol types such as .mht, .xht, etc. it only shows Internet Explorer as an option.

Most likely Firefox hasn’t registered itself with Windows as being able to handle those file types. A quick Google shows, for example, that FF requires an addon to handle .mht files.

I don’t think there’s a directly-accessible UI for setting file associations at that level. There used to be - I don’t remember if went away by Windows 7 - but it was removed due to being considered by MS’s telemetry results a low-usage, confusing and great way to bollox things in general.

You can always try right-clicking files in Explorer and selecting “Open With”. That UI does let you find specific executables and there’s a check mark to always open with what you select.

If you go to the Default Apps settings, you’ll see an option to “Choose default apps by file type”. You can also set defaults by app or protocol. I wasn’t sure if a UI still existed in Win10 either, so this is good to know. (maybe it only exists in Win10 Pro?)

Here are the known file types for Firefox on my PC:

Yeah, that only allows you select from apps that have registered with Windows as able to handle that file type. There was, once upon a time, UI to allow you to add a handler for any program for any file type. It was very clunky (for instance, it helped to know about COM verbs) and as you can imagine made it very easy to screw up your file associations if you managed to get to it.

Ah, ok, I get what you’re saying. I remember that, too.