Account Security Problems

How to Fix Fake Windows Defender Trojan Warning and Support Scam Pop-ups

Rana Garcia Sep 28, 2026 870 views

Question details

The user is encountering a browser pop-up that falsely claims Windows Defender has detected spyware or a Trojan, and it instructs them to call a provided support telephone number.

How to Fix Fake Windows Defender Trojan Warning and Support Scam Pop-ups

Product: Windows Security
Device & OS: Windows
Scenario: Browsing the internet when a malicious webpage takes over the screen with a fake security alert.
Observed behavior: The pop-up locks the browser window, prevents the user from closing it normally, and displays a fraudulent tech support phone number to trick the user into making a call.

Before you start

Do not call the telephone number displayed on the screen, and never provide personal information or grant remote access to your computer to unsolicited callers.

Solution 1Recommended

Force Close the Scam Window and Run a Security Scan

Use system keyboard shortcuts to safely terminate the locked browser window and run a genuine malware scan to ensure your system is clean.

Genuine Windows Security alerts will never prompt you to call a telephone number or lock your screen. These fake warnings use aggressive webpage scripts to prevent standard window closure.

Closing the browser forcefully stops the script from running and immediately neutralizes the immediate threat.

Force close the active window

Press the Alt + F4 keys simultaneously on your keyboard to force the active scam pop-up window to close.

End the browser task if needed

If Alt + F4 does not work, press Ctrl + Shift + Esc to open Task Manager. Locate your web browser (e.g., Chrome, Edge) in the list of processes, right-click it, and select End task.

Open Windows Security

Click the Start menu, type Windows Security, and press Enter to open your PC's built-in security dashboard.

Initiate a system scan

Navigate to Virus & threat protection, click on Scan options, select Full scan or Microsoft Defender Offline scan, and click Scan now.

Force Close the Scam Window and Run a Security Scan

Browser Reset: When you reopen your browser, do not click 'Restore pages' if prompted, as this may reopen the malicious scam webpage.

Solution 2

Post-Scam Security Checklist (If You Interacted)

Take immediate protective measures if you accidentally called the scam number, provided information, or allowed remote computer access.

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Frequently Asked Questions

How can I tell if a Windows Defender warning is real or a scam?

Genuine Windows Defender alerts appear as native system notifications in the corner of your screen or inside the Windows Security app. They will never lock your web browser, play loud alarm sounds, or ask you to call a support telephone number.

Will my computer be infected if I just saw the pop-up?

In most cases, simply seeing the pop-up does not mean your computer is infected with a virus. It is usually just a malicious webpage designed to scare you. As long as you do not download any files or grant remote access, forcing the browser to close will keep your system safe.

Why does the fake warning voice or loud beep keep playing?

Scammers embed auto-playing audio files into the malicious webpage to create a false sense of urgency and panic. Muting your computer's audio and ending the browser process via Task Manager will immediately stop the sound.

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