The exercise system doesn't start correctly in Oracle VM VirtualBox
I've downloaded the exercise system and unziped (using 7-zip). I've added to the latest release of VirtualBox - 5.1.16 r113841 (Qt5.6.2) - but it won't start correctly - get the message "Waiting for network configuration...". I have other VMs "installed", eg. Pega Marketing Enablement 7.13 ML9 which run fine. I've tried re-installing many times with different Network and operating system setups, but without success. Any ideas?