I too noticed that ALL email has been marked as **SPAM** and sent to the junk folder since the last program update (Avast Internet security 7.0) about 2 days ago. I tried using the Outlook Add-in to mark as not spam. This removed the **SPAM** marking and moved it into the Inbox but the very next email from the same sender, even my own email, was again marked as **SPAM** and in the junk folder.
I even tried lowering the sensitivity, everything suggested by the help files. Nothing fixes this issue except to “STOP” the antispam service. It is a pain to keep going to the junk folder and using the add-in to unmark it and move it to the inbox for every single non-spam email and then repeat. Something wrong happened at the last program update from a couple days ago.