I think you've got malware. Please start by investigating extensions, then also run scanning software.

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

• Command+Shift+a (Windows: Ctrl+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 suspicious or that you just do not remember installing or why? If in doubt, disable (or remove).

Any improvement?

Also, scan with something like https://www.malwarebytes.com/mac/

It’s very sad, but many software downloaders/ installers will trick you into installing not only their program, but other programs as well.

You have heard of the fine print in shady contracts, right? Well, some installers you need to look at the itsy bitsy teeny weeny fine print.

You are thinking you are giving the installer permission to install the program you want by using the recommended option. But if you use the Manual Option Instead, you discover all kinds of stuff that you do not even know what it is or what it does.

From now on, everyone needs to Use The Manual Option to put a stop to this.

Note that these programs can also change browser/computer settings.

Yeah I had already checked extensions and removed one, though I don't really think it was the culprit (don't recall the name). Thanks for the Malwarebytes link; it's running now and I already have several items in quarantine and have been notified that a restart is required.

Thanks for the 'Use the Manual Option' hint. I'll try to keep that in mind.

I haven't seen the problem since I posted, but it's only been a day....

I'd also be very interested to know what impacts BrowserDefault and any associated malware may have had on my system. I tried to search for that name but nothing useful showed up.

Thanks again for the help!

Hi, glad you got all fixed up with the nastiness out.

Please Mark the Solution that was the Answer (next to it), Thanks