If you’re using Windows 2k\XP, the version 4.5 has a new mail detection that will work automatically. Please, set up your email account just as avast does not exists. It will detect the pop3/smpt/imap ports and scan your messages. Can you make a try and see if it’s ok? Thanks.
New email detection is automatic and do not require user interaction. Anyway, spam killer applications need manually change email account settings
Do you use any spam killer?
If you’re using Windows 98\Me, Thunderbird must be configurated manually. Change the setting of the email accounts into Thunderbird: Menu Tools > Account settings this way:
Pop3 (Inbound):
Server name: 127.0.0.1
User name: YourUserName#YourPopServerName
Port: 110
Smtp (Outbound):
Server name: 127.0.0.1
User name: YourUserName
(or, in some systems, user name is: YourUserName#YourSmtpServerName)
Port: 25
Note, probably you should run Mail Protection Wizard to have ashMaiSv.exe automatically running at Windows startup.
Otherwise, it seems that Eddy have found a way to solve the troubles with the mail and Thunderbird (http://forum.avast.com/index.php?board=2;action=display;threadid=9069). At least it worked for this person, and may work for a lot of others also.