: File /var/cache/pacman/pkg/jsoncpp-1.8.0-1-x86_64.pkg.tar.xz is corrupted (invalid or corrupted package (PGP signature)).
Do you want to delete it? [Y/n] y
error: failed to commit transaction (invalid or corrupted package)
Errors occurred, no packages were upgraded.

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Update your keyring

sudo rm -r /etc/pacman.d/gnupg
sudo pacman-key --init
--->
Stuck on Generating master-key ?
https://bbs.archlinux.org/viewtopic.php?id=138684
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https://wiki.archlinux.org/index.php/Pacman/Package_signing#How_can_I_collect_entropy.3F

sudo pacman-key --populate archlinux manjaro

sudo pacman-key --refresh-keys