FBI Warning: Your browser has been locked

Most instances of Fake Fbi Browser Lock Ransomware in the security and scam category are fake alerts, but real system compromises do occur and display their own error indicators. Knowing the signs of genuine compromise prevents both over-reaction to fake alerts and under-reaction to real incidents. Signs of genuine compromise that differ from fake alerts: browser settings or homepage changed without your action, new programs installed that you do not recognize, accounts sending emails or messages you did not send, unexpected login notifications from services you use, or antivirus software disabled without your action. Fake alerts are distinguished by: appearing in a browser you were using normally, asking you to call a phone number, claiming a specific dollar amount for repair, or impersonating Windows, Mac, or antivirus brands. For genuine compromise: change passwords for all sensitive accounts from a different device, enable two-factor authentication, review connected apps and OAuth permissions on major services (Google, Microsoft, Facebook), and consider a full OS reinstall for severe infections. For suspected fake alerts: close the browser, clear cookies and browsing history, and install a reputable ad blocker to prevent redirect-based scam pop-ups.