1. pacman produces an error when installing packages
error: restricting filesystem access failed because Landlock is not supported by the kernel!
error: switching to sandbox user 'alpm' failed!
This issue applies to Arch Linux and it’s derivatives (CachyOS, EndavourOS)
You simply need to enable one thing in config.
Go to pacman.conf: sudo nano /etc/pacman.conf
Find the #DisableSandbox and remove the #
(if there’s no such option - just write it in options section)
Save and exit nano: Ctrl+S, Ctrl+X
2. pacman outdated keys
When pacman gives error about unsigned packages when updating the system, update keyring.
sudo pacman -Sy archlinux-keyring