The fake security popup

What it looks like

You're reading the news or looking something up. Suddenly the screen fills with a warning. Maybe a siren sound. Maybe a robotic voice.

⚠ YOUR COMPUTER HAS BEEN BLOCKED Windows Defender — Trojan detected Your banking information is at risk. Do not shut down your computer. Call Microsoft Support: 1-888-XXX-XXXX

The mouse may seem stuck. The window may not close. It may go full screen and refuse to leave.

What's actually happening

Nothing is wrong with your computer.

You clicked a bad ad — often on an ordinary, legitimate website, because ad space is sold and resold and scammers buy it. The "warning" is just a web page designed to look like a system alert. It's a picture of an emergency, not an emergency.

Your computer has no virus. Nothing is being stolen. The only threat on your screen is the phone number.

Microsoft does not put phone numbers in error messages. Neither does Apple. Neither does any real security program. No operating system has ever asked you to call anybody. That single fact ends this scam permanently once you know it.

The same scam, the other way around

Sometimes there's no popup at all. The phone just rings, and it's "Microsoft" or "your antivirus company," saying they've detected a problem on your computer and need remote access to fix it.

Microsoft will never call you about a problem with your computer unless you contacted them first. Neither will any antivirus company. They don't monitor your machine, so they have no way of knowing anything is wrong — which means a call like this is the wrong itself, not a warning about one. Hang up. If you want to check, look up the company's number yourself and call them, the same as everything else on this site.

What happens if you call

A polite, professional person answers, often with a queue and hold music. They ask you to install a program so they can "look at" your machine — AnyDesk, TeamViewer, LogMeIn, UltraViewer. Real tools, used for real support, being used against you here.

Then they show you something alarming: the Event Viewer full of red "errors" (every Windows computer on earth has hundreds; they're routine), or a command window scrolling text. It looks devastating. It's theater.

Then comes the bill. $200 to $600 for "removal," or a multi-year "security plan." And now they have remote access to your computer, your files, your saved passwords, and often your bank login.

Sometimes it goes further. They "refund" you too much money — a fake screen showing $20,000 instead of $200 — and beg you to send back the difference, crying that they'll lose their job. That's how a $400 scam becomes a $19,600 one. Nothing was ever sent to you. The number on your screen was typed by them.

Often it doesn't end there either. This is frequently the opening act of the Phantom Hacker scheme, where the "tech" hands you off to a fake bank, who hands you off to a fake government official.

What to do right now

If the popup is on your screen and you haven't called:

Don't call the number.
Close the browser. If it won't close: hold Ctrl + Alt + Delete on Windows (or Command + Option + Escape on a Mac) and force it to quit.
If that fails, hold the power button until the computer shuts off. This is safe. The warning telling you not to shut down is lying — that instruction exists only to keep you scared and on the screen.
When it restarts, don't reopen the previous tabs.
That's it. You're done. Nothing is infected.

If you already called and let them in: Go to I let someone into my computer and do those steps in order.

How to never fall for it again

Say this out loud once and it'll stick:

A real virus does not give you a phone number.

Real security software cleans things quietly in the background. It doesn't scream at you, doesn't play sirens, doesn't demand a call. Anything that does is advertising, and in this case, advertising a crime.

You handled it

If you closed that window without calling, you just beat a scam that takes hundreds of millions of dollars a year. That wasn't luck — that was you knowing one fact that they were counting on you not knowing.

Tell somebody about it. The next person who sees that screen will be glad you did.

Related: Warning signs · Phantom Hacker