対処方法(84/84) checking keys in keyring [######################] 100% downloading required keys... error: key "901C1C320EB0D45D" could not be looked up remotely error: required key missing from keyring error: failed to commit transaction (unexpected error) Errors occurred, no packages were upgraded.
# pacman -S archlinux-keyringそれでもダメな時
# pacman-key --init # pacman-key --populate archlinux