Many users will see references to an application called MacKeeper on various web sites and via pop-ups on their browser. Not only is it expensive for what it purports to do (freeware applications that do the same or more are readily available), it can sometimes install itself without the user realising it, and it can be very tricky to get rid of.
Most positive reviews of it have been found to have been paid for by Zeobit (developers of MacKeeper) in the form of ‘free upgrades’ etc. For example (posted by fellow contributor Softwater), on their Facebook page and on their webpage they have this apparent endorsement from UNC Charlotte:
Softwater contacted the Director of IT at the College of Arts and Architecture UNC Charlotte, about whether they endorse MacKeeper and his response, quoted here, was:
No, please do not download and install MacKeeper. We have seen problems with this software in the past.
MacKeeper can be regarded as highly invasive malware* that can de-stablize your operating system. It is unethically marketed, with a history of making false advertising claims, by a company called Zeobit and a rip-off.
For more details about Zeobit’s fraudulent advertising and paid-for ‘reviews’, and their dubious marketing practises, read this:
Further opinion on it and how to uninstall MacKeeper malware can be read here:
Do NOT download or use the ‘MacKeeper uninstaller’ from the Zeobit site, as this will cause even more damage to your operating system.
This is also worth reading:
Equally phoney was iAntivirus:
until it was purchased recently (May 2012) by Symantic (makers of Norton anti-virus which does not work well with Apple OS X). Even after having tinkered with it, iAntivirus still fails to do the job properly and cannot be recommended.
There are no viruses that can affect Apple OS X and there is therefore no reason to run anti-virus software on a Mac, but a Mac, like all computers, can transmit viruses and malware to other users particularly those running Windows. Note, however, that Trojans are another matter and can represent a genuine threat, an example of which was the recent 'Flashback Trojan' which you can read more about here:
For further information you may find this User Tip on Viruses, Trojan Detection and Removal, as well as general Internet Security and Privacy, useful:
The User Tip (which you are welcome to print out and retain for future reference) seeks to offer some guidance on the main security threats and how to avoid them.
* The expression ‘malware’ is a general term used by computer professionals to mean a variety of forms of hostile, intrusive, or annoying software.
Not sure what you mean by 'clean up files etc'. Apple OS X does not work like Windows: you don't have to 'defrag' or reinstall the entire system every month like on Windows PCs. In fact, you should never do either.
As long as you have at least 15% of the hard drive free (not used) and sufficient RAM, your Mac will largely look after itself.
If you encounter specific problems, feel free to ask here in these forums. But for the oss glitch:
Repairing permissions is important, and should always be carried out both before and after any software installation or update.
Go to Disk Utility (this is in your Utilities Folder in your Application folder) and click on the icon of your hard disk (not the one with all the numbers).
In First Aid, click on Repair Permissions.
This only takes a minute or two in Tiger, but much longer in Later versions of OS X.
Background information here:
An article on troubleshooting Permissions can be found here:
By the way, you can ignore any messages about SUID or ACL file permissions, as explained here:
If you were having any serious problems with your Mac you might as well complete the exercise by repairing your hard disk as well. You cannot do this from the same start-up disk. Reboot from your install disk (holding down the C key). Once it opens, select your language, and then go to Disk Utility from the Utilities menu. Select your hard disk as before and click Repair:
Once that is complete reboot again from your usual start-up disk.
More useful reading here:
Resolve startup issues and perform disk maintenance with Disk Utility and fsck
For a full description of how to resolve Disk, Permission and Cache Corruption, you should read this FAQ from the X Lab:
Apple's advice on general maintenance: