The Mail Shield is different to the Avast plug-in/add-in for MS Outlook.
If you are using MS Outlook then it should use the Avast plug-in/add-in for MS Outlook, so the Mail Shield Settings wouldn't apply.
I don't use MS Outlook so I can't test to see if it has this function.
1. So i am confused, for what is mail shield settings? Mail shied protect mail apllications.
2. Anyway scanning attachments when attaching is in "Outlook only" settings.
First as I said "I don't use MS Outlook so I can't test" so can't speak from personal experience.
1. MS Outlook has its own Avast email Add-in, you have MS Outlook 2010, if the Avast MS Outlook Add-in is enabled (?) then it will use that, NOT the Mail Shield. The Avast Mail Shield covers email clients using regular email (not webmail), the exclusion being MS Outlook which has its own Avast add-in.
2. Yes it is an MS Outlook only option, but as far as I'm aware that still requires that you have the Avast add-in for MS Outlook enabled.