These messages typically appear because a website was granted permission to send you notifications. Legitimate antivirus software does not send alerts through your web browser's notification system.
Are you seeing this notification in a like Chrome or Safari? This “virus warning” pop-up is a SCAM - Facebook download/view now ( 1.89 MB )
If you are seeing a notification that says it is almost certainly a scam or malicious pop-up . This type of messaging is common in "scareware" attacks, where websites use browser notifications to trick you into downloading malware or paying for fake security software. Why this is a scam These messages typically appear because a website was