Thunderbird manages two email accounts for me...a Gmail and a "@msn.com" account. It does so without problems, until recently when I installed Avast Free for Mac antivirus software. I have both the most recent versions of Thunderbird for Mac, and Avast Free for Mac software (I check for updates daily) Since installing Avast, my "@msn.com" email account has stopped working. I can neither send nor receive any emails. When I uninstall Avast, Thunderbird resumes working normally. When I install Avast, only the "@msn.com" account stops working (the Gmail account continues working normally). I "get" from this description that this is clearly a problem caused by Avast. I am looking to see if anyone knows how to keep the current Avast software in a Mac environment AND have Thunderbirid operate together harmoniously. Can anyone tell me what I need to do in order to achieve this? Please use common language. I'm not particularly techie. Thanks very much!! Chris