You're browsing the internet and suddenly a loud alarm sounds. A pop-up fills your screen warning that your computer has been infected with a virus. It tells you to call a number immediately or your files will be deleted. Your heart rate spikes.
Stop. Don't call the number. This is almost certainly a scam.
What is a fake virus warning?
Fake virus warnings — also called scareware or tech support scams — are designed to frighten you into taking action. That action might be calling a phone number (which connects you to scammers), downloading software that gives criminals access to your computer, or paying for fake "support" to fix a problem that doesn't exist.
They are extremely common in the UK, and they target people of all ages and technical ability.
How to tell if a warning is fake
Real security alerts from Windows or your antivirus software do not play audio alarms, do not ask you to call a phone number, and do not appear in your web browser. If any of these things happen, it's a scam.
Other warning signs include urgent countdown timers, threats that your files or banking details will be stolen, and messages claiming to be from Microsoft, BT, Sky or HMRC.
What to do if it happens to you
First, don't panic. Close the browser tab or window. If you can't close it normally, press Ctrl + W (Windows) or Cmd + W (Mac) to close the tab. If the window is stuck, press Alt + F4 on Windows to force close it.
Once the warning is gone, run a scan with your existing antivirus software to confirm your computer is clean. In most cases, no harm will have been done — the pop-up was designed to scare you, not infect you.
If you did call the number or allow remote access to your computer, disconnect from the internet immediately and seek help.
Already clicked or called? I can help.
If you're worried a scam pop-up may have done something to your computer, I offer a Fake Virus Pop-Up & Scam Check — a remote session where I check your device, confirm whether any real threat exists, and make sure everything is safe and secure.
For ongoing peace of mind, the Bytova Home Support Plan gives you a friendly expert to contact whenever something like this happens.