I had this MK850 keyboard since 2018 or 2019. Today 2025-Oct-03 the button that defaults to forward was not working as I customized it. I had it to Print Screen. Nothing happened. I tried to run the Logitch Options+ app to set it the way it was. I could not run the application. It seemed to begin to start but never did. I had to go and download the latest software.
optionsinstaller.exe
LogiOptionsPlusInstaller.exe
I kid you not it may have taken 2 hours or less.
I had to figure out how to customize the button as there were changes to the software.
Now it is working.