I had the same problem. xdg-screenaver tried to use gnome-screensaver, which wasn't installed. I'm using xscreensaver. My solution was to invoke xscreensaver-command directly, instead of using xdg-screensaver, see here: https://bugs.launchpad.net/caffeine/+bug/1768801/comments/7
I had the same problem. xdg-screenaver tried to use gnome-screensaver, which wasn't installed. I'm using xscreensaver. My solution was to invoke xscreensaver- command directly, instead of using xdg-screensaver, see here: https:/ /bugs.launchpad .net/caffeine/ +bug/1768801/ comments/ 7