With CCleaner you can speed up your slow Mac or PC by cleaning up outdated software and cached files. CCleaner has been the go-to software for protecting and cleaning Windows computers for years. The software was built at a time when Microsoft Windows lacked many of the built-in security features found in operating systems like macOS or Linux. CCleaner can be used to clean potentially unwanted files and invalid Windows Registry entries from a computer. In 2012 CCleaner released a version for macOS.