https://support.mozilla.org/en-US/kb/how-to-set-the-home-page

Type about:config<enter> in the address bar. If a warning screen comes up, press the I Accept the Risk button. At the top of the screen is a search bar. Type browser.startup.homepage

What is the value? Right-click and select Reset to restore its default value; about:home

Whenever I set any web page OTHER than the default home page for Firefox I have the problem of double windows opening up. I should have clarified this.

Let me clarify further. I does not matter what homepage I set--the defaut, Google, DuckDuckGO, etc--when I click on any link and Firefox opens (it is set as the default browser) it opens two windows. One is the default home page that is set in Firefox and the other is the web page that what I am trying to open.

Start Firefox in Safe Mode {web link}

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

Unfortunately, the same behavior occurs in Safe Mode.

Hi

This is a known issue on Catalina.

• Bug 1600153 - macOS 10.15 Catalina - two firefox windows are opened when clicking on external link

(please do not comment in bug reports
https://bugzilla.mozilla.org/page.cgi?id=etiquette.html)

Thank you. I was going to uninstall and reinstall Firefox next but this may be a waste of time. I appreciate the feedback and thank everyone for their time on this.

We can wait for a fix.