Yesterday I installed parabola again on my notebook and had problems when it came to update parabola-keyring.

That is, I executed "# pacman -Sy parabola-keyring" as asked for in the step "Verification of package signatures" of the installation guide.

This would successfully update the package databases and download the package, but fail during the installation with the error message (transcription errors possible):

error: parabola-keyring: signature from "C92BAA713B8D53D3CAE63FC9E6974752F9704456" is unknown trust
!! File /var/cache/pacman/pkg/parabola-keyring-20131022-1-any.pkg.tar.xz is corrupted (invalid or corrupted packages (PGP signature)).
Do you want to delete it? [Y/n] y
error: failed to commit transaction (invalid or corrupted package (PGP signature))
Errrs occured, no packages were upgradeed.

Installation via "pacman -U /var/cache/pacman/pkg/parabola-keyring-20131022-1-any.pkg.tar.xz" (local install with optional signature requirement) would work.