Just installed VirtualBox 5.2 on x64 Windows and downloaded the x64 KDE edition of Manjaro. Install went fine, but there was 143 updates available.
I have seen a few suggestions on similar posts around here such as running this in CLI:
sudo pacman -Syy
sudo pacman -S manjaro-keyring archlinux-keyring pacman-mirrors
sudo pacman-mirrors -f5 && sudo pacman -Syy
sudo pacman -Syu
But the same results still occur:
(143/143) checking keys in keyring [###################] 100%
(143/143) checking package integrity [###################] 100%
error: udiskie: signature from "Ambrevar <ambrevar@gmail.com>" is unknown trust
:: File /var/cache/pacman/pkg/udiskie-1.7.1-1-any.pkg.tar.xz is corrupted (invalid or corrupted package (PGP signature)).
I'm not sure how old the 17.02 iso is from the Manjaro downloads site, but it's probably not good experience for new users to run into this immediately on their first attempt to update the system? I am pretty sure I know how to resolve it as I've had packages in the past where I just need to add trust to key on my system. I usually expect this from AUR packages, and especially not on a fresh install with system packages...