Here's how I solved it: Move /etc/xdg/autostart/caffeine.desktop to ~/.config/autostart (You'll need to be root for it to be deleted from /etc/__) Change ownership of the moved "caffeine.desktop" to yourself, if necessary (it should be writable).
From: https://ubuntuforums.org/showthread.php?t=2206656
Extra:
sudo add-apt-repository ppa:caffeine-developers/caffeine-dev
sudo add-apt-repository ppa:caffeine-developers/ppa
sudo add-apt-repository ppa:nilarimogard/webupd8\nsudo apt-get update\nsudo apt-get install caffeine-plus