Google’s search error that bothered Web surfers on Saturday was caused by human error, said the company in a statement. For a time stretch of about 40 minutes that day, the users of Google’s search engine were warned when trying to search that www.Google.com or any other site in the search results list are potentially harmful to their PC.

The users who tried to access their preferred search result were advised to click on another one.

In response to the glitch, Marissa Mayer, Google’s VP of search, wrote in a post on the Official Google Blog: "What happened? Very simply, human error."

When the error occurred, most people thought the impossible had happened – Google was hacked. Google did not give an official explanation. They just said it was caused by human error.

Google periodically updates the black list of sites that are harmful using data from StopBadware.org, a non-profit organization that investigates consumer complaints and decides which sites are unsafe or harmful.

Basically, in those 40 minutes of search error, Google labeled all the Web sites as potentially harmful. It happened because, accidentally, the URL value of "/" was checked and classified as being potentially unsafe. But the "/" value extends to all URLs, so all the sites were immediately included in the blacklist.

"We will carefully investigate this incident and put more robust file checks in place to prevent it from happening again," Ms Mayer wrote.

Google initially blamed StopBadware.org for the glitch, but then corrected the statement and apologized to the organization and to the users who were affected by the error.