Hi rfsmith48, Yahoo is one of the few search engines that does not come with Firefox, so usually the problem is a rogue extension or external malware. Here are some suggestions for tracking that down:

Extensions

You can view, disable, and often remove unwanted or unknown extensions on the Add-ons page. Either:

• Ctrl+Shift+a (Mac: Command+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons
• type or paste about:addons in the address bar and press Enter/Return

In the left column of the Add-ons page, click Extensions.

Then cast a critical eye over the list on the right side. Any extensions Firefox installs for built-in features are hidden from this page, so everything listed here is your choice (and your responsibility) to manage. Anything that mentions searching? Anything that looks suspicious? Anything you just do not remember installing or why? If in doubt, disable or remove -- don't let unknown programs linger on your system or in any of your browsers.

Any improvement?

External Malware

The following support article lists well-regarded free (or free trial) tools to supplement Windows Defender or your other security software: Troubleshoot Firefox issues caused by malware.

In addition to removing bad programs, you sometimes need to clean up changes they left behind, such as:

• Modified desktop shortcut that shows an unwanted startup page (doesn't sound applicable in this case)
• Autoconfig files that override your configuration at startup
• Policy file that overrides your configuration at startup
• Scheduled task to modify your Firefox configuration

So this post doesn't get any longer, let's come back to those if needed.

Thanks for the quick response. I followed the instructions for "Menu/Addons/about Addons" "Extensions" was in a menu bar at the top of page. When I clicked that, I got a listing of "2,345 extensions found in Search Tools" This was not a tabular listing liked a file directory. When I clicked on several of the suspect Yahoo listings, the program asked me if I wanted to install them. There is nothing to right click and disable or delete......

BTW: I ran Malwarebytes and Webroot yesterday. No indicated problems.

I ran the "Refresh Firefox" procedure. It seems OK now. How often should I run the "Refresh" process?

Thanks again. Rog Smith

I followed the instructions for "Menu/Addons/about Addons" "Extensions" was in a menu bar at the top of page. When I clicked that, I got a listing of "2,345 extensions found in Search Tools"

Sorry, you would need to look at bit lower on the Add-ons page, Extensions panel, to the list of currently installed extensions. Those are below the "Manage Your Extensions" heading.

I ran the "Refresh Firefox" procedure. It seems OK now. How often should I run the "Refresh" process?

Refresh removes the existing extensions, and custom settings, so you are starting clean and you shouldn't need to Refresh again unless you want to. That said, if you connected to a Firefox Account after the Refresh and have Sync set up, problem extensions may return. In that case, please try the disabling/removing steps at that point.