I have reviewed and tested software for 30 years and published 50 cd rom titles. I'm running windows 7 and cclean locks up when it hits index.dat ... so it's a useless program for me. All your Internet traces are logged to index.dat files. To make it worse, you don't have a bug report option. You have to go throught the lenghty registration process and come here to let them know. I would NEVER want bugs posted for the world to consider ... for my software. I rather they just tell me and let me fix it. I still recommend their defragger.