High Pondus, thanks for your interest. I may be that I'm being stupid, I was getting a notification that definitions were out of date and then the error messages I posted above - but now, when I click on Update, I see the information posted in the attached image 5 -so does that mean I'm up to date? In the About Avast screen, I see the attached image info image 6. I thought that suggested a signature file dated in May, but perhaps I'm misreading it?