Symptoms
- Full-screen pop-up with alarming warnings and a countdown
- A phone number to 'call Microsoft support' or similar
- Browser won't close normally or loops back to the page
- Loud alarm sound playing from the browser tab
Likely causes
- CommonMalicious or compromised websiteA site or ad network is showing a fake browser-based warning designed to scare you into calling.
- PossibleBrowser notification spamYou may have accidentally allowed a site to send push notifications that mimic system alerts.
- PossibleSearch result to a scam siteClicking a sponsored or malicious search result can land you on a fake tech-support page.
What to do
- Do not call any phone number shown on the screen or click anything on the page.
- Try closing just the browser tab; if the page won't let you, close the entire browser window.
- If the browser is frozen, use Task Manager or Force Quit to close it entirely rather than clicking anything in the pop-up.
- Reopen the browser without restoring the previous session (choose 'don't reopen tabs' if prompted).
- Go into browser settings and remove notification permissions for any unfamiliar sites.
- Run a quick antivirus scan just to confirm nothing was actually installed.
- Avoid the site that triggered the pop-up in the future.
When to call a pro
If you already called the number and gave someone remote access to your computer, disconnect from the internet immediately and have a professional check for remote-access tools before you use it again.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.