Hi,
Not sure where to post this one as its not realy about asking for help, its more about the goodness of Avast 
Up to a couple of weeks ago I was using a well known AV suite and I was using thunderbird 2 for email and text news reading. I know over time I had a few nasty emails with attachments that the AV suite marked as ‘disinfected’ and I had deleted or thought I had 
Today I did a scan with Windows defender and it found a load of infected mail in my mail profile folder what the ? Anyway windows defender cant remove those infections for some silly reason though I suspect its the way thunderbird stores emails. So I decided just out of curiosity to use a program called Imapsize to export my mail folders into .eml files, I then imported them into another email client, no pop ups for windows defender or Avast at this point.
I had tons of email,way over 2000 and tons I had deleted in thunderbird going back way beyond 2006 ! You could say its more like data recovery than converting email formats. Sorting through those emails showed quite few with attachments, this email client I am using shows the attachment size too, for files that have been disinfected they still had a file size inside the attached zip file. I extracted one attachment and scanned it with Avast, it came up as infected and did its thing, great
I wondered why Avast never picked it up while extracting so I messed with Avast settings and added the *zip extention to ‘scan when writing’ inside advanced setting for Avast file shield.
Now every time I even point my mouse over the mail attachment, up pops Avast with its warning, great, it grabs infected files now but I still have to delete the offending things from the mail folder manually
So Avast is now getting those darn things that my other AV suit missed or left behind ;D Result is one clean mail box !
Mart.