Of course I have not clicked where I'm asked to...

Dropa, Im quite sure that you're wrong. This issue doesn't appear when Firefox is closed. The problem started after upgrade of Firefox to 105.0.1 the other day, only when Firefox is open. McAfee isn't installed in my Mac. Sophos say that my computer is clean. Is there something to switch off in the preferences in Firefox, please?

Where is this so called trojan being found?

Is it in the Cache folder?

Old article but still relevant. https://support.mozilla.org/en-US/kb/Firefox+cache+file+was+infected+with+a+virus

Whether there is something of a trojan or malware etc in Cache or not, it is harmless while there unless you went in that folder and tried to say run that file yourself. It is harmless if left alone and will be overwritten as stuff gets added to Cache or deleted when you delete cache anyways.

Please see the enclosed picture. The message in Swedish translated to English: "McAfee: Firewall crashes via musicinmysoul.biz TROJAN-virus detected. Click here..." Other versions of the message appears now and then but only when Firefox is open. Cant find musicinmysoul.biz in my Mac when searching. I will not press click in the message, as unwanted things could happen. But I don't think anything will happen as McAfee isn't installed. I'll take a look in cache files.

Now removed musicinmysoul.biz from cash in Firefox. I'll see what will happen. Hopefully it solves my problem. I'll come back if not solved. Thank you!

No more problems when musicinmysoul.biz is removed from cash files in Firefox.