Working in the background

Unable to run ccleaner7 working in the background?

That doesn’t tell us why you can’t run it.

Is it getting stuck on the ‘Welcome’ screen?
If so then: Go into Windows Settings and set the display scale to 100%.
Run CCleaner 7 and get past the Welcome Screen.
Set your display scale back to what it was.

If it isn’t launching at all then you may have a faulty install. If you go to Windows Settings > Apps and click CCleaner 7 it should show you options to Repair or to Uninstall.
You can download a new v7 installer from here: Download CCleaner builds | CCleaner Portable, Slim, and more

If you can’t get CCleaner 7 to work then you have the option to roll-back to v6.39: