McKeeper

It is not a virus. It's an unnecessary program with very questionable marketing tactics. Don't bother with it.

It's not a virus, but it is a very nasty piece of software that pollutes your computer with junk and its operation often breaks the computer's normal functioning.

Stay as far away from it as you possibly can. If you want to read some horror stories about McKeeper, just search this forum. You can start with the More Like This list below.

It's a scam that will claim your computer has an infection when there is none, and you need to pay them for a subscription to remove it, in an attempt to extort money out of you.

MVassia those things are all scams that are nevertheless highly successful, due to their aggressive marketing strategies.

"MacKeeper" is not the only example. It's not even the worst offender.

Excerpted from Effective defenses against malware and other threats:

Never install any product that claims to "clean up", "speed up", "optimize", "boost" or "accelerate" your Mac; to "wash" it, "tune" it, or to make it "shiny". Those claims are absurd.

• Such products are very aggressively marketed. They are all scams.
• They generally operate on the flawed premise that a Mac accumulates "junk" that needs to be routinely "cleaned out" for optimum performance.
• Trial versions of those programs are successful because they provide the instant gratification of greater free disk space.
• That increased space is the result of irreversible destruction of files, programs, or operating system components normally protected from inadvertent alteration or deletion. The eventual result will be unreliable operation, poor performance and random crashes that may not become evident for months or even years after their use, when updates to programs or OS X are eventually released.
• Memory "cleaners" that circumvent OS X's memory management algorithms work by purging inactive memory contents to mass storage, which can only result in degraded performance and accelerated hardware failure.

Also see:

http://www.macrumors.com/2015/08/10/mackeeper-refund-settlement/

Do not install MacKeeper (and how to uninstall it if you have):

https://discussions.apple.com/docs/DOC-6221

It contains a major security flaw, recently noted:

http://www.macnn.com/articles/15/05/08/contentious.utility.ignored.apple.guideli nes.created.zero.day.exploit.128538/

There is currently a class-action against MacKeeper:

http://www.macworld.com/article/2927032/ads-for-mackeeper-refunds-will-run-on-fa cebook.html#tk.nl_mwbest

(Please note that references to the original developers, Zeobit, also now refer to Kromtech Alliance Corp, who acquired MacKeeper and PCKeeper from ZeoBit LLC in early 2013.)

This recent court case is illuminating:

http://www.courthousenews.com/2014/01/21/64695.htm