There are hundreds of cleaning tools available for Mac but MacKeeper is one of the best I've ever tried. Effective, super-slick and ultra easy to use, MacKeeper is a new cleaning and maintenance tool that's saved me over 20GB of hard drive space that was being wasted by various files. It differs from some cleaners in that as well as offline cleaning, it also offers online help courtesy of a subscription only Geek on Demand service. MacKeeper's interface is clear and simple with all of the available features listed down the left hand side and details of each in the middle of the screen. I like the way that each time you open it, you have an instant overview of when your last maintenance task was, total disk space saved by MacKeeper etc:

You know a cleaning tool is good when it saves you over 20GB of hard drive space. That's exactly what MacKeeper did for me. To see if it can do the same for you, go to One-Click Scan and MacKeeper will begin to scan your system for files that are duplicated, cached and taking up space in other ways. The scan can take a while and you'll notice a small clock-face next to each feature showing you how much time is left before the task is complete. The time it takes to scan is one of the few drawbacks of MacKeeper but at least you know it's doing a proper job.

I was amazed by how much junk MacKeeper found particularly in the Binaries Cutter (almost 1GB) Logs Cleaner and Cache Cleaner (over 2GB). It also revealed almost 1GB of language files I'll probably never need. The Duplicates Finder was particularly outstanding. I had almost 15GB of duplicated files and MacKeeper allows you to drill down to see where they are. However, be very careful with this as it can remove iMovie files that have been duplicated by iMovie from the raw footage to add to your projects folder. Removing them could mean that you end up with footage missing from your projects.
The Old Files feature was not so impressive either, as it seemed to take metadata from the files to assess the age rather than the actual time they had been left unused on the system. There are other tools such as a Shredder, Data Encrypter and Undelete tool as well as online help with Geek on Demand plus some kind of online registration that tracks your Mac if stolen.

MacKeeper is an amazingly effective, slick and comprehensive tool. You're bound to speed-up and trim your system by using it.

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The tech at the Apple store told me to use OnyX - which is a free program. He felt it was the best out there for Macs. How do you feel about OnyX and how does it match up against MacKeeper? When I was using my Titianium laptop I bought Norton Utilities that was bundled with other software. It stated right on the box that it could be used on OS 10.4. I had been using Norton Utilities for years with OS 9 no problems. But, once I started using it with OS 10.4 on my Titianium - the computer started doing very strong things. It would turn on and off repeatedly. I had to turn it off and take it in to the nearest Apple store. The tech told me that the Hard Drive had a melt down. Everything reinstalled. I had to make a decision if anything should be saved. I said photos and such, plus my mail server. I was lucky that it worked for as long as it did after that, but the hard Drive was really trashed by the Norton Utilities software. I had to have what I could removed from this lap top to the new MacBook I had to buy to replace it. I still have the Titanium hoping to retreive Norton would take no responsibility for what happened. They would not even discuss it with me. So, I will never use Norton anything on my Mac computers again. But, please let me know how you compare OnyX with this new MacKeeper. Is it worth buying? How much does it cost, too!
NO! Have you noticed that many functions require you to be "signed in" to function? They refused to explain why. Plus, the program can run wild and prevent your Mac from booting; in effect, rendering it useless. I bought the full version and regret doing so. It may speed you up a bit at first and clear disk space, but there are freeware programs that work as well and with no risks.