E.tre456_worm_osx is a scary alert that may unexpectedly come up via your Mac browsers, including Google Chrome, Opera, Mozilla Firefox and Safari. It is the result of adware to be currently active in your Mac computer. Sadly, there are very many systems these days that are getting more and more vulnerable before various viruses that are popular on the web. In the light of such information, you’re strongly advised to perform a thorough scanning of your workstation using proven virus removal software that is able to detect and delete this kind of infection.