Not very useful

Great, it works OK with your main drive. But it’s useless for external drives. And it’s not a “disk doctor,” it just gives you information that ANYONE could figure out after 10 minutes on the User Support Communities at Apple. It’s not giving me anythingj I don’t need. And it haphazardly erases every file that’s a cache. That’s not very useful.

This app is overpriced for what it can and can’t do.

LeftCoastMan about Disk Doctor: System Cleaner