Any ideas what to might be?
Yes, its your fault.
Generally, the answer is one of the following :
(a) You have a virus on your computer
(b) Someone on your home network has a virus on their computer
(c) Someone is using your home network for nefarious means (hello WiFi
)
or, more rarely
(d) Your Google-fu is of high quality and Google can't tell the difference between you and a fancy algorithm. I have fallen into this category once or twice when doing "desktop research" projects. However, generally if you fall into this category, you will be presented a CAPTCHA alongside the error message.
But basically, you need to fix the cause, because if you don't, Google's systems will keep on complaining.