How to prevent Norton from making changes to my compacted email files?

The Norton Security virus scan made a change to one of my compacted email files, and several of my emails are now unreadable.

How can I have Norton just warn me about the possible malware, and allow me to delete the offending email attachment?? 

The problem seems to always be an attachment to an email that I have casually flipped into the trash.  Most of the time I go back and permanently delete the obvious virus carriers from the Trash folder, but sometimes I forget.  If the virus scan would just remind me - and not try to delete contents of the compacted file - the whole process would work just fine.

Thanks,

Phil