A frightening warning can make an ordinary browser page look like an emergency. A message that demands a phone call, payment, gift card, download, or remote access deserves caution. You can pause before doing anything the message asks.
Do these things first
Do not call the phone number in the warning. Do not click a payment link, buy a gift card, install a remote-control app, or give someone a password or one-time security code.
Try to close the browser tab or browser window. If the message will not close, use the computer's normal restart option. A full-screen warning may look like it controls the computer even when it is only a web page.
- Use a support number that you found independently, not one shown in the warning
- Take a photo of the message if you can do so without clicking it
- Write down what happened just before the warning appeared
- Leave any suspicious download unopened
If someone already connected to the computer
End the remote session and disconnect the computer from Wi-Fi or its network cable. If you cannot end the session, turn the computer off. Use a different trusted device for important account or financial steps.
Contact a bank or card issuer through the number printed on the card or its official website if you shared payment information or sent money. Change exposed passwords through the service's official app or website, starting with email and financial accounts. Do not reuse the new password on another account.
What a device check can cover
A check can look for common remote-access programs, unwanted browser extensions, unusual startup items, and available security updates. It can also help you make a list of accounts that may need attention.
No single scan can prove that every account and device is safe. Serious ransomware, identity theft, an active business breach, or regulated business data may require a security specialist.
Make future warnings easier to handle
Keep the official phone numbers for important accounts in a place you can reach without using the affected computer. Turn on automatic updates when they are appropriate, keep a current backup, and use a different password for each important account.
If an unexpected caller says there is a problem with your computer, bank, subscription, or refund, end the call. Contact the company yourself through a number or app you already trust.