Remove "weknow.ac" Malware in Chrome?
You need to open the "Terminal" application (use the search functionality at the top-right to find it). Then copy and paste, one by one, the commands from my above post into the terminal prompt, hitting enter after pasting each.
defaults write com.google.Chrome HomepageIsNewTabPage -bool false
defaults write com.google.Chrome NewTabPageLocation -string "https://www.google.com/"
defaults write com.google.Chrome HomepageLocation -string "https://www.google.com/"
defaults delete com.google.Chrome DefaultSearchProviderSearchURL
defaults delete com.google.Chrome DefaultSearchProviderNewTabURL
defaults delete com.google.Chrome DefaultSearchProviderName