Microsoft support policy for the use of registry cleaning utilities

This article describes the Microsoft support policy for customers who use registry cleaning utilities that rely on unsupported methods to extract or modify the contents of a Windows Registry.
The Windows registry is a database of settings for all hardware, software, and user preferences on your computer that controls how Windows interacts with your hardware and applications. Windows continually references the registry in the background and it is not designed to be accessed or edited.
Some products such as registry cleaning utilities suggest that the registry needs regular maintenance or cleaning. However, serious issues can occur when you modify the registry incorrectly using these types of utilities. These issues might require users to reinstall the operating system due to instability. Microsoft cannot guarantee that these problems can be solved without a reinstallation of the Operating System as the extent of the changes made by registry cleaning utilities varies from application to application.
 
Full Article
 
Daniel 😉