Update Procedure for the Paranoid

If you believe that Murphy was an optimist then the following is for you.

Let me say again that this is not a "requirement" BUT if you have been having problems (there are never any problems with a Mac are there?) or if want to be sure of not loosing anything and being able to restore your old OS then this should give you the best chance.

At a minimum I would have a full backup before any "major" upgrade. But all of you are backing up all the time already using Time Machine, right? If you are running OS X Lion and Time Machine you have Lion Recovery built in. However, Lion Recovery will ERASE your disk before it runs. Time Machine does not back up everything but Carbon Copy Cloner does. Accept no substitutes.

So here goes:

1. Make sure you have a backup.
2. Resolve any problems you have been having. If you are having major problems with your current OS installation, try addressing them first. (Re-applying the Combo installer for your current version of OS X is one way of doing this.) While OS updates can be the solution to many problems, if you are having major stability problems (i.e., random crashes, odd noises, inability to authenticate) then be sure to address them before applying the update.
3. Download the COMBO installer from Apple's site for the version of the OS you want to upgrade to. Remember, the update that is installed via Software Update is changes only. If you want ALL changes and updates since 10.x, you MUST download and run the COMBO installer. This is most important if you have been have ANY problems.
4. Boot from the CD or DVD that came with your Mac and run Disk Utility to (1) Repair Disk and (2) Repair Permissions. If you do not have a CD or DVD just boot into SAFE MODE run Verify Disk to see if there are any problems if Disk Utility does not report any problems only then run Repair Permissions. If Verify Disk reports a problem then you MUST boot your Mac from another volume or the CD or DVD so you can run Repair Disk. If Disk Utility is able to fix the problem only then run Repair Permissions. If Disk Utility can not "fix" the problem you have a major disk issue which must be addressed at once.
5. Reboot into SAFE MODE.
6. Run the COMBO installer you downloaded.
7. After the reboot run Software Update... until there are no more updates.
8. Run Disk Utility and Repair Permissions. (I know we did this already but believe it or not Disk Utility will find more permissions that need repair. Trust me. I could not print or type in search boxes after one upgrade until I did this.)