A new "rogue" software program, called Macsweeper, is making the rounds, claiming to be security software. It says "The imbibed set of features locates all the junk and useless data on your computer and deletes them to reclaim the wasted space" (whatever that means), and when you run it, tells you that you naturally have such junk and useless data, and offering to resolve the problem for $40. But it's all a scam; it just wants your money for nothing. Each time you run the program, it will spot different "dangerous" files that must be cleaned, until, most likely, you have paid.
Don't buy this scam. While other software may claim to clean up your Mac, this program is nothing but digital snake oil. It's clear that an unknown "security" company, whose English is dubious, and whose website is a blatant rip-off of another security vendor's site, is not who you should trust for such software. Trust the companies you know well, like Intego, who have devoted years to keeping Macs safe.