Launch on startup

[wtw84]

CCleaner launches on startup, even though the corresponding box in the settings is not checked.

[nukecad]

You are not the first to ask this.

It's a simple missunderstanding of what 'Launch the CCleaner app window each time the computer starts' actually does.
And of what does make CCleaner keep running in the background.

'Launch the CCleaner app window each time the computer starts' simply runs a clean at start and then closes CCleaner.
It puts a flashing icon in the system tray when the computer starts, but ony for seconds while the clean is running and the icon disappears once the clean has finished. It can be so quick that you don't even notice it.
(Despite what it says it doesn't actually open any window).

There are two functions that will run CCleaner in the background, so that a CCleaner icon remains in the system tray (not flashing) and CCleaner is shown in Task Manager as running.

1. Smart Cleaning: If you have Smart Cleaning enabled it needs to run in the background to monitor for junk building up, or for a browser being closed.
2. 'Keep CCleaner updated automatically': This needs to run in the background to periodically check if an update is avaiable. (I believe it checks every 12 hours).

If either of those options is selected then it runs in the background, so you will get the icon in  the system tray and Task Manager will say CCleaner is running.
If you manualy close CCleaner from that icon, or from Task Manager, then those two functions will stop working until next time you start CCleaner or start your machine.