Account Security Problems

Fix Fake Windows Defender Security Warning Scam Pop-ups

Adam Davis Oct 1, 2026 868 views

Question details

The user is encountering a fake pop-up message claiming that Windows Defender has blocked their computer and urging them to call a provided phone number.

How to Remove Fake Windows Defender Security Warning Pop-Ups

Product: Windows Security
Device & OS: Windows
Scenario: Browsing the internet when a sudden, unclosable security warning pop-up appears on the screen, attempting to lock the browser.
Observed behavior: A browser window displays a fraudulent Microsoft error message instructing the user to call technical support, often freezing the screen or making it difficult to close normally.

Before you start

Do not call the phone number provided in the pop-up, do not click on any links within the message, and never grant remote access to your computer to anyone claiming to be from Microsoft support.

Solution 1Recommended

Safely Close the Scam Pop-Up Using Keyboard Shortcuts

Force-close the frozen browser window to safely dismiss the fraudulent security warning without clicking on any malicious links.

These pop-ups are essentially malicious web pages designed to go into full-screen mode and disable standard navigation buttons, making it seem like your computer is locked. Forcing the browser to close will immediately stop the scam.

Use the Alt+F4 Shortcut

While the fake warning is active on your screen, press the Alt and F4 keys on your keyboard simultaneously to instantly close the active browser window.

Force Close via Task Manager

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

Restart Your Computer

If your screen is completely frozen and you cannot open the Task Manager, manually restart your computer by pressing and holding the physical power button on your device.

Safely Close the Scam Pop-Up Using Keyboard Shortcuts

Genuine Microsoft Alerts: Genuine Microsoft error messages and Windows Defender alerts will never include a phone number for you to call. They also appear in the Windows Security app, not inside your web browser.

Solution 2

Run a Security Scan and Prevent Future Pop-ups

Ensure your computer is completely free of malware and install browser protections to block similar scam pages from appearing.

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Frequently Asked Questions

Why am I getting this Windows Defender pop-up?

This pop-up is generally triggered by visiting a compromised website, clicking on a misleading advertisement, or having an unwanted browser extension installed. It is simply a deceptive webpage, not an actual alert from your computer.

What happens if I call the number on the scam pop-up?

If you call the number, scammers will try to convince you that your computer is heavily infected. They will likely ask for remote access to your PC, demand payment for unnecessary 'fixes', or attempt to steal your personal and financial information.

Can these pop-ups infect my computer with viruses?

Simply seeing the pop-up does not usually infect your PC, provided you do not download any files it suggests, click on its links, or grant the scammers remote access. Closing the browser safely is generally enough to protect your system.

How do I tell a real Windows Defender alert from a fake one?

Real Windows Defender notifications are system-level alerts that appear in the Windows Action Center or the dedicated Windows Security app. They never appear as web pages in your browser, and Microsoft will never ask you to call a support phone number.

Microsoft Office Security Issues