Avast insists on adding an extension to Chrome “Avast Online Security Added”. This is truly bad behavior to try to sneak in modifications to a user’s programs. How can shut this off permanently? And I plead with Avast to remove this sort of behavior from Avast, it is anti-security to have programs stealthily doing this sort of thing.
Go to add/remove programs and then go to change and deselect the avast online security feature if you dont want the extension.