Ok, so for future reference (I found the instructions in https://www.qubes-os.org/doc/vm-sudo/ to be not completely clear):
The files mentioned in the first part of https://www.qubes-os.org/doc/vm-sudo/, namely: /etc/sudoers.d/qubes /etc/polkit-1/rules.d/00-qubes-allow-all.rules /etc/polkit-1/localauthority/50-local.d/qubes-allow-all.pkla are to be created/edited in the VM, not in Dom0. This effectively solves the problem. -- You received this message because you are subscribed to the Google Groups "qubes-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to qubes-users+unsubscr...@googlegroups.com. To post to this group, send email to email@example.com. To view this discussion on the web visit https://groups.google.com/d/msgid/qubes-users/2cd7e068-7238-4356-9220-9e8cafdc1718%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.