From the avastUI > Settings > Active Protection > Mail Shield > Settings (wrench iconl) > Behavior - General section > “Uncheck” Insert note into clean message (outgoing
I recently installed Avast and some receipents are spam filters are having issues with this message in the emails sent. I have Avast 2014.9.0.2013 installed on my system. I followed the instructions and the message is still being inserted in my outgoing emails. After changing the setting I even rebooted my pc and it is still being inserted.