
This probably is more a Windows than Firefox issue, especially as it seems related to incomplete uninstall preceding the reinstall. After repeated uninstall/reinstall cycles, I still can't get FF to register as an available handler for web protocols (but not ''all'' web file types: mhtml and shtm are not available, which may be an omission by the FF installer). I have experienced the same problem after a temporary downgrade to Firefox 52ESR (to recover important functionality from old extensions).

Now I am happily puttering along in Firefox and Firebug while everyone else in the known universe is browsing and debugging in Chrome.All of the proposed solutions presume that W10 will offer Firefox as one of its browser options, but Catherine's question begins from the fact that it is not offered there, so the proposed "solutions" don't even address her problem, let alone solve it. The values were set to ChromeHTML and I changed them to FirefoxURL. Within each of these is the value Progid. Each of these keys has another subkey named UserChoice. The registry key is HKEY_CURRENT_USER\Software\Microsoft\Windows\Shell\Associations\UrlAssociations. However, I was able to modify the registry to overcome this problem. My best guess is that Firefox being missing from the Default Program list was due to it being installed as a limited user without administrator rights.

I was surprised when I was unable to set Firefox as the default browser to use when clicking links. I installed the most recent version, 38.0.1, and it installed to my profile folder because I ran without administrator privileges. I’ve been using Firefox since it came out and haven’t transitioned to Chrome like everyone else has. Recently I was on a Windows 7 computer with Chrome and IE installed.
