It is not working. I cannot even open the application.
I would recommend uninstalling the software, then also deleting everything from the following folders if present:
~/Library/Application Support/CCleaner
~/Library/Preferences/CCleaner
~/Library/Caches/CCleaner
~/Library/Logs/CCleaner
~/Library/Group Containers/8M34BTQQ45.group.com.piriform.osx.ccleaner (it could possibly have a different string of random letters/numbers)
Finally, restart the computer (just to be on the safe side), and then install the software again.
If problems persist, please contact our Support team via the Contact Us form located here: https://support.piriform.com/hc/en-us/requests/new?ticket_form_id=86507 or email support@ccleaner.com with this information and the steps you've taken so far so that our support team can investigate further.