As a workaround, you can type this command (according to https://askubuntu.com/a/1175736/426176 , thanks to N0rbert from askubuntu) :
sudo sed -i 's#<policy domain="coder" rights="none" pattern="PDF" />#<policy domain="coder" rights="read|write" pattern="PDF" />#' /etc/ImageMagick-6/policy.xml
As a workaround, you can type this command (according to https:/ /askubuntu. com/a/1175736/ 426176 , thanks to N0rbert from askubuntu) :
sudo sed -i 's#<policy domain="coder" rights="none" pattern="PDF" />#<policy domain="coder" rights="read|write" pattern="PDF" />#' /etc/ImageMagic k-6/policy. xml