I just recently upgraded to the Leopard 10.5.2 update and I thought I’d share my short but sweet process on performing upgrades of OS X (aka applying or installing a system update) without regrets:

1. Wait a day or two.

Sometimes updates have an issue with them ever after extensive beta testing, people report bugs, and then these get fixed and rolled back into the update. You usually don’t need to be on the latest right away. The folks at O’Grady’s PowerPage recommend waiting 72 hours.

2. Empty your trash and restart your Mac.

This gets you to a clean state. Also if you’re on a laptop, make sure you’re plugged in.

3. Make a bootable clone with SuperDuper! and make sure you can actually boot from it.

This is pretty easy to do – in the Options, set the “On successful completion” to “Restart from YourBackupVolume”. Also I repair permissions before copying. This may seem tedious but its worth it in case something happens. You’ll be able to go back, keep working and try updating again.

I personally use a Firewire 400/800 drive I bought from Other World Computing (aka macsales.com). I connect with FW800 with my MacBook Pro and FW400 with my iMac. OWC is really focused on the Mac market and their drives have been fast and reliable.

4. Unmount and unplug your bootable clone.

For good measure, do the same with any other external drives. This is a good precaution – if something goes wrong, then your clone is safe and so are your other drives.

5. Download and use the Combo Updater.

I search for this (ex: google “combo updater 10.5.2”) and download it, rather than using Software Update to get the system update. This seems to be more reliable. It also lets you skip point releases, so you can go from 10.5.0 to 10.5.2 without having to install 10.5.1 inbetween.