My Apple G5 Freezes on Startup

Check your Apple G5 to find the causes of boot-up problems.

If your Apple Macintosh G5-based computer freezes each time you press the power button, you know you have a troubled system. Until you work your way through some careful troubleshooting, it's tough to separate the expensive problems from the merely inconvenient. Even a simple problem can prevent your computer from operating properly.

Boot From Installer

Find out whether your system can boot from an operating system installation disc, either the one that shipped with your Mac or a retail installer for an operating system that's compatible with your system. You can use an installer for Mac OS 10.2 Jaguar, 10.3 Panther, 10.4 Tiger or 10.5 Leopard. To identify your system's OS compatibility, visit the Apple website. If your computer can boot up from an installer disc, the operating system installed on your hard drive may be corrupt. To correct the problem, reinstall your operating system.

Disk Utility

While your G5 computer is booted up from an OS installer disc, run Apple's Disk Utility application to check your operating system and hard drive for trouble. Apple includes Disk Utility on its installer discs so you can use it to repair your start-up drive, which requires that you boot from an alternate source. If Disk Utility finds and repairs errors, try starting up your system again and see if it's corrected.

Apple Hardware Test

Your G5 shipped with a CD or DVD that runs Apple Hardware Test, or AHT. AHT is a diagnostic tool designed to check your RAM, hard drive, video card and other internal components, then provide feedback detailing the causes of any trouble it finds. Run AHT in extended mode and write down any error messages it reports. Contact an Apple Authorized Service Center or the Genius at your local Apple Store to find out what the error codes mean to determine the best course of repair.

Other Considerations

Some hardware problems can contribute to boot-up failures and freezes. When the battery that backs up your essential system settings begins to fail, your system may refuse to start. Boot-up failures can trace to a bad power supply. Some G5 computers suffer from motherboard problems caused by a batch of defective electrical components. Other G5s developed problems with the liquid cooling system included on some models.

References

• Apple: Mac 101
• Apple: Mac OS: Technical Overview of Disk Volume Structures
• Apple: Using Disk Utility to Verify or Repair Disks
• Macworld: Diagnose Hard-Drive Disaster
• Apple: Power Mac G5, Apple Hardware Test 2.1 - Interpreting Certain Error Messages
• Cult of Mac: How To Fix Common Mac Startup Problems [MacRx]
• MacCetera: Specialty Services - iMac G5 Main Logic Board Repair
• Accelerate Your Mac: PowerMac G5 Coolant Leaks/Repairs

Resources

• Mac OS X Leopard: The Missing Manual; David Pogue; 2007