The most difficult Apple Mac OS virus we have ever come across ….. Weknow.Ac Weknow.ac resisted all Anti-Virus and Malware removers but was eventually removed after many, many attempts and hours of research, trial and error. How do I know if my computer has the Weknow.ac virus? Open up any browser …. does your search page look like the following or similar? If so, you have the Weknow.ac virus and you need to get rid of it ASAP Following suggestions on another website (MacReports) we managed to clean up Safari browser …. How To Remove Weknow.ac Malware (macOS) The advise offered here regarding Google Chrome did not work, we know this because it is still impossible to change the default search-engine away from we know.ac How did I get the weknow.ac virus? Well in our case we were looking for a Microsoft site called “Success with Teams” and instead of typing successwithteams.com mis-spelled it as sucesswithteams.com which landed me on the following page where I was fooled into thinking that Flash Player needed upgrading We found more advice on removing the we know.ac virus on the Apple Communities Website, where we came across two solutions: Wipe and reformat your HDD by going into recovery mode.(Only advisable if you have a current Time Machine Backup) …. “weknow.ac” changes a group of Chrome policies so as to set a new default homepage, new tab behavior, etc. You can see your current Chrome policies by typing chrome://policy/ into your URL bar. If you’re infected, it should be very obvious as the half-dozen or so policies changed by weknow will be displayed. Use the command line to delete / modify the affected policies. You do this by opening up “Terminal” and copy and paste each of the following entries below. I did each one at a time. I copy and pasted the first line and then hit enter and then went to the next until I had finished all 6 below: 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 Quit Chrome and restart it and voila the virus will be gone. I tried everything and 3 phone calls with Apple and this was the only thing that worked.   If you think you have this Virus and your attempts to remove it have failed, bring your computer to our office and our Apple qualified experts can do it for you.   :jk: