Date: 2008jul4 Update: 2009aug24 Update: 2017sep18 OS: Windows Q. Windows: What's the best registry cleaner? A. I have used CCleaner before. I'm not sure if its the best but it didn't break anything and seemed complete. Its free with a suggested donation. http://www.ccleaner.com Good - it previews the changes its doing to make and lets you select which you want. Bad - it installs Yahoo Toolbar and Messenger by default. So pay attention when installing it. And avoid that. In Sept 2017 it was revealed that it had been infect with malware for a month. So if you have a good version, keep it. I definitely disable its monitoring service. It deleted my Ultra VNC Viewer recently visited sites (MRU). I should have checked. BleachBit does not clean the registry.