How to do defragment disk on Mac?

Norton Utilities and Techtool Pro are third party applications for Macs. Cocktail (10 day free trial) can be used for cleaning caches, optimizing ect. Or just launch Disc Utilities choose the disc you want to check and follow directions.

As the above but also remember to both leave your Mac on over night and/or turn it off occasionally. The computer does some maintenance scheduled at night, and at start-up (see Mlsstl and the reason for restart advice from the Sfar link).

There is another Mac utility called MacJanitor, it cleans up the disc without having to leave your computer on all night.

You can download it here for free.

One more suggestion, especially if you run any Microsoft applications on your mac or do file sharing.

Download Peer Guardian and it will block attempts at spying from government, Edu, Internet providers, Spyware, Microsoft Corp and others.

It too is free. I've had file sharing sessions where as many as 2 thousand hits were made on my computer, all turned away by this free application.

http://phoenixlabs.org/pgosx/

Another exceptionally useful Mac utility is MainMenu. It runs all the routine maintenance scripts that Albert mentions plus lots of other useful tasks like rebuilding your Spotlight index, repairing disk permissions, clearing caches and histories and removing temporary files, all from a single icon in the menu bar.

First of all, I would like to appreciate all members' information and knowledge. Second, I wanted to say thank all very much. Thanks again gentlemen.