To see if avast! is scanning emails, check one of these points:

  1. Is the avast icon (the special one of email scanning) be shown in the system tray?

  2. Is your email header with the lines X-Antivirus: avast! (VPS 0XXX-X, XX/XX/2004), Inbound message and X-Antivirus-Status: Clean? (Right click the message, choose Properties and Details)

  3. Are clean notes added at the bottom of the email? (Internet Mail provider settings)

[b]You can test the security of your email system here: http://www.gfi.com/emailsecuritytest/[/b]

About the clean notes into the message body, can you try ‘Settings’ on my signature?
UseAlternateRtfSyncing value under [MailScanner] section:

Another mechanism for inserting notes into the body of emails in Microsoft Outlook. RtfSyncing is concerned with Rich Text Format. In emails, the user typically save both Rich text (HTML) and plain form of message. When you modify one type of message, RTFSync is the right function to synchronize text of message to the second form. Disable = 0.

See screenshot of settings here: http://forum.avast.com/index.php?board=2;action=display;threadid=9514

Start avast antivirus > Right click the skin > Help > Setting up the Mail protection > Manual setting of mail protection
If you have Windows 98\Me, the change of the login settings is normal while using avast. See http://forum.avast.com/index.php?action=display;board=2;threadid=7913;start=0#msg64228