I don't know if this is the same in the Outlook/Exchange provider/plugin (I don't use MS Outlook), but here is what you doe for the Internet Mail provider, it is probably the same or similar.
Click on
Internet Mail provider and then on
Customize.
Go to
Advanced tab and select
Silent Mode and the default answer
No.
Personally I don't use silent mode, because I want to know what is going on with my system. If someone is getting so many warnings of virus infection, infected emails, etc. that they become intrusive, then it is time to review their security practice - filter emails at source, delete from server rather than download them, etc.
I use MailWasher Pro but there is a free version that only works with one email account. Not only does it filter spam but you can also filter suspicious emails at source, the email server, you then only download the email you want.