How do I get the Caffeine app working on macOS Mojave?
Caffeine is still working! However, Apple has upped its security and privacy model a bit and caffeine fell prey to that. What you have to do to get it working properly again is the following:


Open System Preferences
Click Security &amp; Privacy
Click the Privacy tab
In the left column, select Accessibility
If needed, click the lock icon in the lower left and enter your password to unlock your settings
Click the + button and select your Caffeine app to allow it to control your Mac
Restart Caffeine