DO THIS! Before you update!

Question

Want a trouble free 10.4.7 update? Then do ALL of the following 7 steps. Sure, its a few extra steps, but certainly worth the trouble.
Here the list:
1. backup your data and/or clone your drive.
2. Repair permissions. (before and after update)
3. Use a utility like ONYX to clean your system caches.
4. Use a utility like Disk Warrior to verify and/or rebuild your directory.
5. Download the Combo updater (do not use Software Update)
6. Unplug all Firewire and USB drives and devices from computer
7. Run installer
I ALWAYS do all of the above before an OS update and I've never had a single problem.
Most of the time (not always,) when people are blaming Apple for problematic updates, they should be blaming themselves for not maintaining and backing up their systems properly. An OS update on top of a system with directory errors is the number one reason for erratic behavior. Disk Utility costs $100, but it takes care of directory errors. Be safe not sorry.
Powermac G4 dual 1.25, 2gb Ram, 17 + 20 inch Apple display   Mac OS X (10.4.6)  

Answer 1

Here's the long version I posted elsewhere:
Every time an update is released, ton's of people claim it broke their system.
And, I've never had a single update mess up my computer since OS 8.1.
I just today installed the 10.4.7 update on two different machines, and both are still running as good as they were before (and actually slightly improved).
There are several things that everyone should do before installing a major update like this.
First, and foremost, if there is anything even remotely wrong in your existing installation, updating is going to cause them to show up. So, even if you are not aware of an existing problem, updating will bring it out of hiding.
So, That brings us to the first point.
1) Make sure everything is definitely 100% perfect before you update. It will not help if anything is wrong before you get started (even if symptoms are not present, problems can be hiding somewhere).
So, fix any potential problems before you update
2) Repair Permissions immediately before updating. This can spare you a ton of trouble.
3) Disconnect any external accessories (FireWire & USB drives, Cameras, Graphics Tablets, etc.).
4) Check your disk hard drive for errors. Boot up from your restore CD and Check your disk for errors using Disk Utility. Use repair if any are found.
5) Reboot your system before installing any updates. Do not install updates while you have any programs open, or on a system that you have been using. Always reboot immediately before installing an update. This way you know that all your programs are 100% for sure closed.
6) Disable any anti-virus program you have installed. This will ensure that your anti-virus system does not block your update from being installed properly (if it saw the activity as a potential virus attack).
7) Never install a major update without backing up your entire hard drive to another bootable drive (such as an external FireWire hard drive). I did this twice before this update (once on each system). It only takes about a half-hour to an hour. It will save you a lot of problems later if something goes wrong.
If you have a backup, and something goes wrong, you just restore from your backup, and you're right back to where you were before the update.
Every single company will tell you to backup before you install an update. It's right there in the warning that you must click past (you just have to read it).
That brings us to the next one:
8) Actually take the time to read that license agreement and warning that comes up on the screen before you actually install the update. Yes, it may be 10 pages long, but it's going to tell you about things you should know before you install.
9) For OS updates, choose the "Combo" version when you have a choice (you'll need to go to Apple's website to download it).
The Delta version only updates files that have changed since the immediately prior release.
The software update version replaces even less than the "Delta" version. It only downloads the specific updates you need to go from your updated version of the current OS to the next one.
The "Combo" version replaces all the files that have changed since the major release (10.4.0).
So, with the Combo update, you will often have better success since your corrupted system files are most likely to be replaced.
The Combo update is basically almost like a fresh install that keeps your settings in-tact.
The Delta update is more like a band-aid that applies the changes.
So, go for the Combo update.
10) After you install the update, and the system is back up and running, reboot and start up again. This clears out anything that may be left in memory from the installer (even if you just rebooted to complete the installation, reboot again).
11) Reset the PRAM after installing a major update. This never hurts, and can clear out any small bugs stored in your settings.
12) Don't forget to repair permissions again after the update. You can never do this too frequently. Do it often, and you'll save yourself some trouble.
Hope this helps those of you who have not yet performed your upgrade (and those of you who will install future upgrades).
These basic preparations steps will save you down-time. And, an hour or so of preparation to save 2 or more days of down-time is definitely a fair trade.
Hope this helps. Good luck all.