Does the unwanted window appear if you use Ctrl+n for a new window or click the Home button?

If yes: Could you double-check that you don't have dual home pages? Firefox allows you to specify multiple addresses separated by a vertical bar, and you may need to delete it there. These articles have more info on that:

• Startup, home page, tabs, and download settings
• How to set the home page

If no: You may have an unwanted extension that is launching the extra window. Try disabling ALL nonessential or unrecognized extensions on the Add-ons page. Either:

• Command+Shift+a (Windows: Ctrl+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then cast a skeptical eye over the list on the right side and, if in doubt, disable or remove.

Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step.

Any improvement?

brekeen said

When I first open Firefox a second window opens and overrides Firefox as a search engine

Fantastic Thank you so much for your assistance. Wish I knew how this happened in the first place!