How do I defrag my iMac

Kappy's Personal Suggestions for OS X Maintenance

For disk repairs use Disk Utility. For situations DU cannot handle the best third-party utilities are: Disk Warrior; DW only fixes problems with the disk directory, but most disk problems are caused by directory corruption; Disk Warrior 4.x is now Intel Mac compatible. TechTool Pro provides additional repair options including file repair and recovery, system diagnostics, and disk defragmentation. TechTool Pro 4.5.1 or higher are Intel Mac compatible; Drive Genius is similar to TechTool Pro in terms of the various repair services provided. Versions 1.5.1 or later are Intel Mac compatible.

OS X performs certain maintenance functions that are scheduled to occur on a daily, weekly, or monthly period. The maintenance scripts run in the early AM only if the computer is turned on 24/7 (no sleep.) If this isn't the case, then an excellent solution is to download and install a shareware utility such as Macaroni, JAW PseudoAnacron, or Anacron that will automate the maintenance activity regardless of whether the computer is turned off or asleep. Dependence upon third-party utilities to run the periodic maintenance scripts had been significantly reduced in Tiger and Leopard.

OS X automatically defrags files less than 20 MBs in size, so unless you have a disk full of very large files there's little need for defragmenting the hard drive. As for virus protection there are few if any such animals affecting OS X. You can protect the computer easily using the freeware Open Source virus protection software ClamXAV. Personally I would avoid most commercial anti-virus software because of their potential for causing problems.

I would also recommend downloading the shareware utility TinkerTool System that you can use for periodic maintenance such as removing old logfiles and archives, clearing caches, etc.

For emergency repairs install the freeware utility Applejack. If you cannot start up in OS X, you may be able to start in single-user mode from which you can run Applejack to do a whole set of repair and maintenance routines from the commandline. Note that AppleJack 1.5 is required for Leopard.

When you install any new system software or updates be sure to repair the hard drive and permissions beforehand. I also recommend booting into safe mode before doing system software updates.

Get an external Firewire drive at least equal in size to the internal hard drive and make (and maintain) a bootable clone/backup. You can make a bootable clone using the Restore option of Disk Utility. You can also make and maintain clones with good backup software. My personal recommendations are (order is not significant):

1. Retrospect Desktop (Commercial - not yet universal binary)
2. Synchronize! Pro X (Commercial)
3. Synk (Backup, Standard, or Pro)
4. Deja Vu (Shareware)
5. Carbon Copy Cloner (Donationware)
6. SuperDuper! (Commercial)
7. Intego Personal Backup (Commercial)
8. Data Backup (Commercial)
9. SilverKeeper 2.0 (Freeware)
10. MimMac (Commercial)
11. CloneTool Hatchery (Shareware)
12. Clone X (Commercial)

The following utilities can also be used for backup, but cannot create bootable clones:

1. Backup (requires a .Mac account with Apple both to get the software and to use it.)
2. Toast
3. Impression
4. arRSync

Apple's Backup is a full backup tool capable of also backing up across multiple media such as CD/DVD. However, it cannot create bootable backups. It is primarily an "archiving" utility as are the other two.

Impression and Toast are disk image based backups, only. Particularly useful if you need to backup to CD/DVD across multiple media.

Visit The XLab FAQs and read the FAQs on maintenance, optimization, virus protection, and backup and restore.

Additional suggestions will be found in Mac Maintenance Quick Assist.

Referenced software can be found at www.versiontracker.com and www.macupdate.com.

nanny2, welcome to Apple Discussions.

How much free space do you have on your hard drive? A low amount will cause slowness.

Re: Defrag. Look at *About disk optimization with Mac OS X*
http://docs.info.apple.com/article.html?artnum=25668

 Cheers, Tom 😉

nanny2:

Kappy's suggestions for maintenance should make a significant difference to the performance of your computer.

As the Apple Article linked by Tom defragmentation is not normally required in Mac OS X. However, note this exception:

If your disks are almost full, and you often modify or create large files (such as editing video, but see the Tip below if you use iMovie and Mac OS X 10.3), there's a chance the disks could be fragmented. In this case, you might benefit from defragmentation, which can be performed with some third-party disk utilities.

Mac OS X requires free disk capacity for swap files and directory growth. If your HDD is 40 GB of less in total capacity, you need a minimum of 5 GB as free space (available capacity), 40 GB and over requires a minimum of 15% of total disk capacity as free space. If you are close to the limits, defragmentation will help provide the contiguous free space needed. You can either use a utility like Tech Tool Pro or DriveGenius. The article suggests this alternative

Another option is to back up your important files, erase the hard disk, then reinstall Mac OS X and your backed up files.

😉 cornelius

You do not defrag mac hard disks. They do not have that problem like a windows computer does. They stay optimized.