Can you provide a link and the exact message?

Here is a site that I visited: https://www.youtube.com/watch?v=TALNVq0C_HM Here is a link to the site that a new tab opened to: https://www.cisa.gov/rumorcontrol This has happened while at other sites too. Another site has popped open too: https://www.archives.gov/electoral-college/2020

When you open the YouTube link: Did those tabs open on their own? Did you click something? Did they open right away or was there a delay?

I did not click anything other than the link to the desired content. The tabs opened on their own. There was a delay. I was able to replicate this when I first contacted support. It seems to have stopped.

You may have ad/mal-ware. Further information can be found in this article; https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware?cache=no

Run most or all of the listed free to use malware scanners. Each works differently. If one program misses something, another may pick it up.

Microsoft essentials and Malwarebytes are installed and running regular scans. Will see what else shows up with other program scans. I'm skeptical this is malware unless it's government implemented.