With the impending 10.4.11 update (presumably Apple's final major update to the Tiger OS) looming over us, I thought I'd go over some best practices for safely updating one's computer.
There are many opinions out there concerning what to do before running an OS X update. Some people perform an full backup of their hard drive before installing updates, even smaller security or application updates. It's actually not a bad idea, especially if you're in a production environment with deadlines that need to be met. This can be too much work for many, so let's explore the alternatives.
Some believe that the best practice is to boot your Mac off of your OS X installer disc and run the Disk Utility application. When in Disk Utility, Verify and Repair your disk as well as repair permissions. This is a good way to go with since the OS on the disk drive itself isn't running and can fully perform any repairs that are necessary.
Other people believe that running a third party application such as Cocktail, Onyx or AppleJack is best practice as it can address more problems than the Disk Utility application can.
I've personally had great results with running AppleJack. It requires the computer to be booted in single-user mode which may intimidate many users, but it is one of the best tools that I've come across to tame the savage Mac. AppleJack is donationware and doesn't require a license.
So what is the safest way to update your Mac? Wait. Unless you're experiencing problems that are preventing you from using your Mac, just wait. There have been plenty of updates released that caused more problems than they were worth either by Apple or by a third party vendor. It just happens from time to time.
So be patient and wait. There are plenty of people out there that run Macs simply as test machines specifically to see what can break them and those people love update time. They post their experiences to forums for everyone to read.
What's in my arsenal? Disk Warrior, Cocktail, AppleJack, Font Finagler, Preferential Treatment, SuperDuper!, WeibeTech hardware and the Terminal.
At the very least, make sure to back up your home folder on a regular basis. Buy an external FireWire drive that can store all of your data. At the very least, this protects all of your important data.
Erik