Every now and then when applying updates to my Antergos (Arch) Linux desktop I get an error like
$ sudo pacman -Syyu ... error: libvirt: signature from "Christian Rebischke (Arch Linux Security Team-Member) <Chris.Rebischke@archlinux.org>" is unknown trust :: File /var/cache/pacman/pkg/libvirt-4.6.0-3-x86_64.pkg.tar.xz is corrupted (invalid or corrupted package (PGP signature)). Do you want to delete it? [Y/n]
Accepting the default option means the update fails. If using the GUI client there’s just a message saying the update failed with no further explanation
It is fixed by
$ sudo pacman -S archlinux-keyring
This kind of error is one reason why I’d never consider using Arch in a work environment.