i have downloaded debian-9.4.0-amd64-DVD-1.isowhen i double click on it, it says cannot open. the iso debian-9.4.0-amd64-DVD-2 and iso debian-9.4.0-amd64-DVD-3
i can open and read. the same thing happened with debian 9.0.0. i am using mac pro 10.10.5 to download / open / and hopefully burn.