What 'MacKeeper' is and why you should avoid it | iMore →

This is very important and I’ve increasingly seen it on some of the Macs of my clients. When they call me in with inevitable problems and weirdness with their systems, I immediately remove it and explain to them why it is to be avoided. As Macs get more popular they are increasingly a target for this kind of stuff that we in the Mac community have never really had to bother with before.

I also commonly see an Adware package called Genio along side of it. I, personally, suspect it is installing this too but have yet to able to confirm the connection. I use AdwareMedic for that with tremendous success.