Help needed with unwanted pop up. claims to be mcafee. On a recently purchased macbook pro. refurbished

Thanks- did all that. And going through safe boot, reinstall and still it comes! Safe maybe but maddening. I can't even switch off notifications for this pesky thing. It's mining into my brain --- if not my computer's! Apple support assisting now - next step back up, wipe the drive and reinstall.

Got there! Having backed up and ready for wiping the disk, the last lovely Apple adviser (who's had this bug himself) spotted a bit of malware lurking under the guise of systems notification - re "confirming not a robot". We turned it off, but apparently can't remove it.

Hasn't popped up since - so looks like my problem is dealt with if not solved (unless of course it's just sleeping - waiting to be reactivated from somewhere in the upside down world).

For clarity/accuracy for anyone else, this thing is more of a sideways slide entry than a pop-up; its very like the official apple notification to share screen (same red too).