Use a trusted antivirus like Malwarebytes or Microsoft Defender to ensure no background "adware" is causing these pop-ups to reappear [1, 5].
The phrase is a widespread scam notification or "fake alert" used by malicious websites to trick you into downloading malware, adware, or unwanted software [1, 2]. Summary of the Threat download/view now ( 280.47 MB )
To frighten or entice you into clicking, which typically leads to the installation of browser hijackers, "PC cleaners" that are actually junkware, or credential-stealing Trojans [4]. Use a trusted antivirus like Malwarebytes or Microsoft
Usually triggered by "malvertising" (bad ads), redirected links from pirated content sites, or "push notifications" you accidentally allowed in your browser [2, 3]. Usually triggered by "malvertising" (bad ads)
It mimics the look of Windows, macOS, or Chrome interface elements to look like a "system message" [2].
Remove recent cookies and site data to stop the redirects.