There is a bug in Ccleaner version 6.3.0.10002. It will keep turning on Windows System Restore which will eat up valuable disk space on a Hard Drive each time Ccleaner is enabled to clean the Hard Drive.
A fix has been issued by Ccleaner by downloading the previous version of Ccleaner 6.2.0.9938 click the link below. If one does use Windows System Restore for Restoring a Hard Drive then there are no issues, this is just for ones that do not use this feature. There is no need to uninstall Ccleaner the slim version for download will rewrite over the latest version. Ccleaner will update to a newer version once this bug is fixed. One may have to disable their System Restore once again but after that it stays disabled.
CCleaner upon loading is enabling the disabled Windows Restore feature.. - CCleaner Bug Reporting - CCleaner Community Forums