On one of my PCs Synaptic stopped working. The Zorin installer still works fine. It sees Synaptic, so I removed Synaptic and reinstalled it. Still not able to launch Synaptic. I tried a couple of reboots. Still no change.
From the Main menu editor, I found Synaptic under System tools and found that the command line code is: synaptic-pkexec When I entered sudo synaptic-pkexec the error returned is:
No protocol specified
Unable to init server: Could not connect: Connections refused
As I searched further, I found a fix: xhost +si:localuser:root
So, now that I fixed my problem, what could have goofed it up to begin with?