MacKeeper is Malware
There's a great post about MacKeeper on the Apple Discussion Forum.
MacKeeper has been described by various sources as highly invasive malware* that can de-stablize your operating system, adding that it is unethically marketed, with a history of making false advertising claims, by a company called Zeobit, and a rip-off.
Quick Link: How to uninstall MacKeeper
* The expression ‘malware’ is a general term used by computer professionals to mean a variety of forms of hostile, intrusive, or annoying software.