UPDATE: The reason why I avoided following Malwarebytes suggestions was because I had scanned the latter and my direct scans revealed there was no malware, etc. After several attempts to open the Firefox browser and always receiving the above link/message, I became suspicious. I WAS WRONG! After I posted the above and having seen similar complaints elsewhere, I took another look and decided to independently follow their suggestions and it worked. Now I have a working browser for Mozilla Firefox. Too bad I had already uninstalled Malwarebytes. Since I am not an expert, I am not promoting the link and message but rather posting my experience.

Hello,

You could start Firefox with a new profile to see if the issue persists.

You could also backup your bookmarks via the Library.

Thanks for your quick reply. Above your suggestions, I had posted an update and how I had solved the problem. Initially, when I searched the link there were other similar inquiries and I became overly careful, thus my post here. In the end, all is well that ends well. Thanks again.