Mojle wrote:
Checked this too and everything looks ok.
Maybe it had more to do with the site you were visiting—ignore it, don't click it.
In all honesty you did not paint a very big picture... on going, a one off pop-up, every browser, old issue, new issue, etc.
Just because it is made to look like a notification does not mean it is official mac notification ..
popup messages of this sort are a scam—
as following the procedures at the site may lead to damage to the user’s device.
pop-ups
Recognize and avoid phishing messages, phony support calls ...
Effective defenses against malware and other threats… - Apple Community
Effective defenses against malware and ot… - Apple Community
If you are still at a lose you can get a good look at your System config. and reveal conflicts or issues, you can download/run this trusted utility https://etrecheck.com
If you need help interpreting the report you can post it here in its entirety in the "Additional Text" box in the editing toolbar below, in your reply.