Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
You don't need to defrag your Mac. The HFS+ filesystem does that automatically to improve overall speed.
 
In some cases you want to defragment~

For example, let's say you have 40GB in free space and you want to partition 35GB to BootCamp; the utility might give you a bunch of errors telling you that the partitioning can't be done, files can't be moved, etc., and the only way you can install Windows is to wipe the drive, reinstall OS X, and then go from there.

Well for that you can either reinstall like they say (which could be tedious since you need to move files back from backup as well), or defragment your drive. Defragmenting your drive doesn't always work, but it worth a try since it's less time consuming overall it does make drive access faster.

So the other replies are correct in that you don't need to defragment in OS X in most normal circumstances, but in some cases defragmenting your drive is useful.

Anyways, I use iDefrag to do it. I have Drive Genius 3 and it also defragments, but iDefrag has a visual which helps knowing when it will be done.
 
I recall reading somewhere that if you add/delete/move a large amount of files it can be helpful. I still don't know the verdict on that.

I believe there was a gentlemen who did a lot of video and photo work. Constantly importing, moving and deleting. He got utility from it. For the average user I don't think its important.
 
Don't worry about this.
Sometimes leave it turned on during the night with the lid open and it will do the maintenance by itself.
 
Don't worry about this.
Sometimes leave it turned on during the night with the lid open and it will do the maintenance by itself.
The maintenance scripts have nothing to do with defragmentation. Also, you don't need to leave it on overnight. If your Mac is asleep or off when the scripts are scheduled to run, they'll just run the next time your Mac is on.
 
You don't need to defrag your Mac. The HFS+ filesystem does that automatically to improve overall speed.

Partially agreed!! It all depend on the type of work you performing on your Mac. Apple itself says the file system can defrag limited (upto 20MB) space. If you need to transfer, delete, shift large number of files usually you could need to do defrag. For me as a vedio editor I need to do it usually and utility that is used is Stellar Drive Defrag. I started with free download but soon decided to buy, it actually worth buying....:eek:
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.