I use the latest Chrome on a win 8.1 laptop.
It seems that about 10% of time when I click on links from various sites, I get the following message.
The URL "null" is not valid. Did you mean www.nolo.com?
(the page says COMODO from http://nxd.securedns.dns.com/
Then always, when I click the browser back-arrow and try it again, it works properly.
This is very annoying.
Long ago I deleted any alternative search engines from my settings. Google is still the only one.