I've installed v5.74.8198 on two different computers today. Both still had the issue of CCleaner still loading in the system tray when the user profile boots up.
I've noticed for it to work correctly, you have to uncheck the box "Tell me when there are junk files to clean" and THEN uncheck "Enable Smart Cleaning" and THEN select Yes to disable.
If you go the opposite direction, unchecking "Enable Smart Cleaning" first you never get the "Disable Smart Cleaning" popup, you then cannot uncheck "Tell me when..." You have click on a different menu, then click back to the "Smart Cleaning" tab, and then you can uncheck "Tell me when..." BUT, even though both options are unchecked, CCleaner will still load at the next boot because Smart Cleaning is still enabled.
So anyway, don't start unchecking with "Enable Smart Cleaning". Once you start with unchecking "Tell me when..." and then unchecking "Enable...", only then you'll get the "Disable Smart Cleaning" Yes/No popup and will then be disabled and won't load with the user profile.
EDIT: BTW, my automatic update setting is disabled too.