Guides / Website

"Your computer is infected, call Microsoft" pop-up - what it really is

The full-screen virus warning with a phone number, why it can't detect anything, how to close it, and what happens if you call.

Updated 17 September 2026·2 min read

⚠ WINDOWS DEFENDER SECURITY WARNING
Your PC has been blocked. Trojan spyware detected. Do not shut down your computer. Call Microsoft Support: +1 (866) xxx-xxxx

The screen goes red, an alarm sounds, a robotic voice repeats the warning, and the browser won't close.

Short answer: it's a web page. Nothing has scanned your computer and nothing is infected. A website (often reached through a mistyped address or a bad ad) is showing you a page designed to look like a system alert, using full-screen mode and a loud audio file. Microsoft, Apple and Google never put phone numbers in warnings.

What happens if you call

A "technician" asks to connect to your PC with remote-access software to "run a diagnostic". They open harmless system logs and read them as proof of infection, then charge $200-$500 to "fix" it - or, worse, log into your bank while connected and take much more. Some install real malware on the way out so they can call you again.

How to close it

  • Windows: press Ctrl + Shift + Esc for Task Manager, select the browser, End task. Or hold the power button if the keyboard seems stuck.
  • Mac: Cmd + Option + Esc, select the browser, Force Quit.
  • When you reopen the browser, don't restore the previous session.
  • Nothing else is required. If it makes you feel better, run Windows Security or Malwarebytes - they'll come back clean.

Other versions

  • "Your Apple ID has been locked, call Apple."
  • A phone call to you from "Microsoft" about a virus they detected (Microsoft doesn't call people).
  • A pop-up on your phone saying the battery is infected.

What to do

  1. Don't call, don't let anyone connect to your computer.
  2. If you already let them in: disconnect from the internet, uninstall the remote tool (AnyDesk, TeamViewer, UltraViewer, LogMeIn), change your passwords from another device, and call your bank if you paid or logged into it.
  3. If you paid by card, ask your card issuer for a chargeback: the service was fraudulent.
  4. Older relatives are the main target. Tell them: no real warning ever has a phone number.

Not sure? Paste it

Paste the text of the warning or the page address into Scamed - it checks the domain, spots the phone number and explains the pattern.

More guides