igor0
5
As I said - some of them store its internal data as password-encrypted archives (ZIP, for example). These files are identified as ZIP archives by avast! - and it tries to unpack them (and scan their content). However, it fails - since it doesn’t know the password necessary to unpack them. Therefore, you get the warning that the file couldn’t be scanned.
But you don’t have to worry about the infection in this case.