Hence advanced section
There is a pretty comprehensive description of CCleaners various features and functions on the Piriform Documents site.
Which includes of course a description of the "Advanced" Windows section:
http://docs.piriform.com/ccleaner/ccleaner...d-windows-files
The problem is I think, that the majority of users never bother to read them, and that's maybe because there isn't a clear enough link to the Documents site, with a warning as to the importance of going their first before running something on blind faith.
And we've all done that at sometime.
The "Online Help" link in the bottom left corner of the CCleaner GIU could I think be improved upon.