For the past few weeks, Google has shown the message "Our systems have detected unusual traffic" almost every time I search. I'm not using a VPN, haven't installed any new browser extensions, and haven't knowingly downloaded anything suspicious. I've checked similar discussions, but the usual explanations don't seem to fit. What could be causing this, and how can I diagnose it?
4 Answers
The activity might be coming from another device on your network rather than your computer. Check phones, laptops, smart TVs, streaming devices, the router, and installed apps for anything unfamiliar. Update their software, remove suspicious apps, change your Wi-Fi password, and make sure the router is still receiving security updates.
Google can also trigger this when searches happen very quickly or when you’re making lots of similar research-related searches. Private browsing may make it appear more often because there’s less session history available. Try clearing Google cookies, using a normal browser window, slowing down automated-looking search patterns, and testing another browser to see whether the warning follows the network or the device.
Your public IP address may be shared with a lot of other users through carrier-grade NAT. Google sees many searches coming from the same address and may mistake the combined activity for automated traffic. Your ISP could also have recently assigned you an IP that was previously associated with spam. Restarting your modem may give you a different address, and your ISP can confirm whether you’re behind shared NAT.
I hadn’t considered shared NAT. I’ll check whether my ISP uses carrier-grade NAT and ask if my public IP recently changed.
Since you’re seeing it repeatedly, compare the result on mobile data versus your home Wi-Fi. If it only happens on Wi-Fi, the likely cause is your public IP, shared NAT, router, or another device using the connection. If it follows the computer across networks, run a malware scan and review browser extensions and installed applications.
Nobody else knowingly uses my connection, but I’ll inspect the smart TV and other connected devices as well.