There's a bug in duplicate finder that essentially makes it useless. It is unable to distinguish between multiple directory links ("hard links, NOT shortcuts or symlinks!) to the same file. This shows up big time on a Win7 system with Cygwin installed, as the files in "bin" are hard links to the .exe's in another folder (usually something like "usr\i686-pc-cygwin\bin". The same problem will show up many duplicates in \windows\system32, but CCleaner "thoughtfully" (not!) won't scan there.
Yup, dup finder finds duplicates all right, but they can point to the same exact data in a file system and deleting one of the "duplicates" will not affect the amount of storage used, but may break some software. For those that want to experiment, take a look at the Command Prompt keyword "mklink". The Cygwin command "ln" will create hard links while "ls -l" will show the link count to a given file.
There should be a CCleaner option to screen out hard links that point to the same-on disk bits. Or, better yet, show in the report which are "duplicate" links to the same file versus actual duplicate files.
Cheers, -Tom
