How was your firefox installed?

Hello dathomas49,

Would you do this please :

First go to Windows Settings => Apps and choose 'Allow all apps'.

Then uninstall and reinstall Firefox to see if that will make Firefox appear as app.

Does that work  ?

I may have been unclear.

Firefox DOES appear in the list of apps shown under “Apps & features” and “Allow apps from anywhere” is set.

But if I go to “Default apps” → “Web browser” THAT only shows Edge and IE as available options. (Plus “Look for an app in the Store”, of course)

I downloaded “Firefox installer.exe” from the Mozilla website. I right-clicked on the program and chose “Run as administrator”

When you're in Windows Settings => Default Apps, click om either browser that is listed there, and you will get a dropdown that includes Firefox - click on it ....

See this article : https://support.mozilla.org/en-US/kb/make-firefox-your-default-browser

Does that work  ?

NO. That does not work. I do that and ONLY see Edge and IE.

dathomas49 said

NO. That does not work. I do that and ONLY see Edge and IE.

Weird ....

When you go to Windows Control Panel => Default Programs - is Firefox listed there  ?

If not, would you please download Firefox from here :

https://www.mozilla.org/firefox/all/

(and choose your preferred laguage)