From Daring Fireball:
I Believe in Murphy’s Law: “How I upgrade to a new version of Mac OS X, from 2007″:
So, in short:
- Do a complete backup clone to an external FireWire drive.
- Test that the backup is indeed bootable and up to date.
- Unplug the backup drive.
- Pop in the installer DVD and launch the “Install Mac OS X” app.
[Update: Starting with Snow Leopard, instead of booting from the DVD directly, you should instead pop in the installer DVD and launch the “Install Mac OS X” app on the disc. This will reboot your machine from the DVD, yes, but first it will download any necessary software updates that have come out since the disc was pressed. It’s a subtle but very nice improvement to the installer.]
Of course, now that I have a multi-drive MacPro, I will probably just install 10.6 on a clean new drive…