I’m setting up an old and slow laptop (EeePC 701) as mainly a console-only machine, but I do have XFCE4 on there for my kid to play around with, which he has to start with startx.
I don’t have policy-kit installed, so when he tries to launch Synaptic, XFCE freezes up. The output on the console says pkexec was not found.
Instead of installing pkexec and policy-kit, I just symlinked gksudo to pkexec.
sudo ln -s /usr/bin/gksudo /usr/bin/pkexec