I skimmed the forum and other places, and the impression is NOT to use antivirus plugin, especially with kaspersky. I'm running kis 2017 and installed the bat v7 after kis was up and running for some weeks.  kis settings say that its mail-av is "on" so is there anything else to do.  Older info indicated that plugin for thebat was not needed and actually slowed down the email without adding any better protection.  thanks for feedback.