Unable to deactivate Performance Optimizer after it's enabled

I see no direct option to do this. The only option is to "wake" sleeping programs, but it seems "CCleanerPerformanceOptimizerService.exe" will always run in the background,

Or must I uninstall CCleaner and never enable CCleaner Performance Optimizer, again?

The above should be included in the FAQ, but it's not.

you can go into windows "services" and disable the "CCleanerPerformanceOptimizerService"-service.

make sure that you have no programs disabled by ccleaner's performance optimizer before disabling the performance otimizer service.