DO NOT USE ANY SO CALLED APPS CLAIMING TO "CLEAN", "OPTIMIZE" OR "SPEED UP" YOUR MAC!!!! EVER!!!!
Apps like MacKeeper, MacSweeper or any other maintenance apps like CleanMyMac 1 or 2, TuneUpMyMac, SpeedUpMyMac, MacCleanse or anything like these apps, installed on your Mac, while they appear to be helpful, can do too good a job of data "cleanup" causing the potential to do serious data corruption or data deletion and render a perfectly running OS completely dead and useless leaving you with a frozen, non-functional Mac.
Plus, these type of apps aren't really necessary OR needed. They really aren't.
There are manual methods to clear off unnecessary data off of your Mac that are safer and you have complete control over your Mac and not just leave a piece of auto cleaning software in charge of clearing off data off of your Mac. Their potential of causing OS X issues outweighs the implied good and benefits these types of hard drive or memory "cleaning" apps are written to do.
These types of system 'cleaning" apps are very poorly written and are really a scam to rob newbieand novice Mac users of their hard earned cash for a poorly written maintenance program that will do much more harm to a perfectly normal running OS X system than the good that the app developers purport these types of apps will do.
Plus, the software companies that write these apps make it hard to easily uninstall these apps if something DOES go wrong and these apps work in a way where you have no recovery or revert function to return your Mac back to its former, working state in the event something does go wrong.
It is best to never, EVER download and install these types of apps.
The risk to your system and important data is too great a risk!