Is there anyone with the same problem with me? Last Friday, I downloaded the latest Avast Mac Security from cnet download and installed it without any problem. Today, when I open it from launchpad, it’s window appeared indeed. But it crashed at once when I can see its window and then nothing. I tried many times without no difference. Should I reinstall it or do something else? In addition, my Thunderbird cannot receive any emails now. It said my emails server had disconnected. Is a problem caused by Avast? Thanks for any advice.