Right after logging it I get a pop-up on my Linux Mint 22.3 system, saying:
“Some dependencies not installed. Both ‘sox’ and ‘xenity’ are required for this applet to have all its functionality including notifications and audible alerts.”
I checked, both are installed, so that’s not the problem. Note that Linux Mint renamed xenity as Zenity – but it’s the same program.
The Real Problem
The Battery Monitor applet labeled “Battery Applet with Monitoring and Shutdown (BAMS) by PDCurtis” is the issue.
The Solution
Just remove the Battery Monitor applet.
Right-click the Battery Monitor applet on the panel and choose Remove. If it isn’t visible, open System Settings → Applets → Manage, find Battery Monitor, and remove or disable it. Log out and back in to check whether the warning stops.
And just a tip, the desklet version “Battery level indicator”works without an issue.