For Mac OS or Mac OS X, how do I obtain and install system software updates?

Apple and Apple-authorized resellers distribute major releases of Mac OS and Mac OS X. However, Apple will often release free updates between major commercial releases. In Mac OS 9 and later, you may use the Software Update feature to download and install updates to your operating system software and to other programs distributed by Apple. You must be connected to the Internet to use this feature.

1. In Mac OS X 10.3.x and later, from the Apple menu, select Software Update... . In OS X 10.2.x and earlier, from the Apple menu, select System Preferences... , and then from the View menu, select Software Update.

   In Mac OS 9, from the Apple menu, choose Control Panels and select Software Update.

2. Click Update Now. The software will check for updates.
   
   
3. If updates are available, a window will open with a list. Select or deselect those updates you do or don't want to install, and click Install.
   
   
4. If prompted with a warning that you will have to restart your computer, click OK.
   
   
5. The software will download and automatically install or update. Click Restart if requested once it has finished.

Note: In some cases, you may have to run the Software Update multiple times before it can completely update your system.

Manually installing the update

You may also download software updates and install them manually. The Apple Downloads web site and the Apple Support Area are two good places to start.

At Indiana University, IUware also has updates for recent versions of the operating system.

Software updates that you download come as disk images encoded in MacBinary or BinHex format. You will need StuffIt Expander to decode the files and Disk Copy or Disk Utility to mount the update parts as disk images before installing.

If you are using Mac OS X, once you have the update, double-click the installer and follow the instructions on the screen. If you are using Mac OS 9.x and earlier, these instructions will help you make a smooth upgrade:

1. Boot from an alternate disk containing Mac OS system software. By booting your computer from a disk other than the one you are updating, you reduce the likelihood of corrupting the operating system. A valid System Folder must be present on a disk in order to boot from it. This disk may be a utilities floppy, Mac OS CD-ROM, or another volume or hard drive. For information on how to boot from a CD-ROM or alternate volume, see In Mac OS or OS X, how can I boot from a CD or DVD and/or ignore my startup disk? To boot from a floppy, shut down the computer, insert the floppy in the drive and then restart the computer.

   If you cannot boot from an alternate disk, you can still update your system. If the system update you are installing is on a floppy or hard disk, start your computer with extensions off.

2. Run Disk First Aid on the volume you will be updating. Using Disk First Aid will ensure that the disk and its file structure are in good working order before an update.
   
   
3. Update the hard disk drivers with Drive Setup. When Apple updates Mac OS, often it will release a new version of Drive Setup with the latest drivers. You should try to keep your drivers updated. Sometimes the update installer will update the drivers as part of the installation process. To update the drivers manually, launch Drive Setup, highlight the disk you wish to update, and from the Function menu, select Update Driver.
   
   
4. Install the update. Double-click the installer, and choose the correct volume to update. Be sure to read any Readme files that come with the update. These may include compatibility notices about commonly used software, as well as other special information.

Also see:

• For Mac OS X, where can I obtain updates and new releases?
• In Mac OS X 10.3, how can I make SMB connections to Windows servers?