From CCleaner v5.46, this feature is now known as ‘Smart Cleaning’.
We decided to rename Monitoring because some users assumed (because of its name) that this feature reported some data to us, which wasn’t true. The purpose of this feature was only ever, and still is, to check your system’s junk levels to display contextual prompts to clean or trigger cleaning (such as when a lot of junk has built up, or when you close a browser after using it).
As well as renaming this feature to ‘Smart Cleaning’, in v5.46 onwards CCleaner’s Smart Cleaning options have been explained more clearly so you can better understand the cleaning preferences available to you.
Please note that Smart Cleaning is only available in CCleaner Professional, which is the paid version of CCleaner.