It keeps on running after I close it. I see it in Process Explorer.

2 lines are running. 160k and 5k of Private Bytes. Company Name is Piriform Software.

In Settings, Background sync this is unchecked: "Don't allow sites to finish sending or receiving data"

Is this normal? It runs in the background after its closed. That is not cool. Is there another setting I might have missed?

Interesting, I was not able to reproduce this when I tested it with a default install of CCleaner Browser; do you have any extensions installed, perhaps?

You might also want to turn off the Performance > "Quick Launch" setting, as that could allow CCleaner Browser to run in the background to expedite these tasks.

Also: On startup > "Launch CCleaner Browser automatically when your computer starts".

Thank you John. Performance > "Quick Launch" setting was enabled. That must have been it.