“Our systems have detected unusual traffic from your computer network.”
It appears that Google doesn’t really like software that automatically runs queries on their system, and so they make sure that you’re a human using the network by requiring you to complete the captcha.
I disabled the SEO Quake browser extension for the time being and will probably only enable it when I specifically need it at the time.
If you’re seeing this warning on Google, there are a few steps you can take to try and fix it:
1. Scan your computer and any computer on your network for malware
Use an anti-virus scanner to make sure that all of the computers on your network are clean.
2. Remove recently installed browser extensions, add-ons etc
A browser extension caused this issue in my case, but it may not be the same for you. If you recently installed any browser add-ons, you should try disabling them to see which one is the culprit.
3. Renew your IP address
Simply, unplug your router and plug it back in 10 seconds later to refresh your IP address. Of course, you may want to let everyone know in the office or the house that you’re knocking the internet off for a bit 🙂