Today marks the official ship date for Mac OS X 10.3 "Panther" (some users have already received their installation CDs). Over the next few days many MacFixIt readers are going to be partaking in the upgrade experience. So today would appear to be a good time to revisit our recommendations for upgrade procedures that can reduce the number, and severity, of problems you might experience. (In this discussion, we're focusing on those users upgading from an earlier version of Mac OS X.)
First, keep in mind that Panther is a major upgrade to Mac OS X, with significant changes to both the visible feature set and the underlying code. As such, many third-party utilities and applications -- especially system add-ons -- will need to be updated by their developers to ensure compatibility. Be sure to check with the developers of your frequently used software to ensure that you have Panther-compatible versions. (For example, the website for Default Folder X, the popular Open/Save dialog utility, warns that versions 1.8 and earlier will cause all applications to crash under Panther; users should be sure to update to Default Folder X 1.9 or later.) If you have third-party system add-ons -- preference panes, menu utilities, contextual menu plug-ins, Services, etc. -- that are not compatible with Panther, be sure to disable them by removing them from the appropriate folder inside /Library or ~/Library. Likewise, if a particular application isn't compatible, be sure to remove it from your Login Items preferences, if applicable, so that it doesn't launch at login. If you're not sure about specific software titles or add-ons, disable them until after the upgrade, and then try enabling them one at a time to test them for compatibility.
Second, although you should be backing up important data regularly anyway, it's especially important to back up such data, or even your entire hard drive, before undertaking any kind of major system upgrade. If for some reason you encounter serious problems, it's a lot easier to simply restore your system from backup than to try to rebuild it from scratch.
Finally, if you want to avoid many problems, be a conscientious upgrader; although there are always going to be issues with updates and upgrades, many of the reports we receive at MacFixIt after minor or major system updates cover issues that are actually problems with the user's own system. For example, minor disk and/or permissions corruption can prevent an update from installing properly, and sometimes changes from an update can reveal existing issues that were previously unidentified. By taking a few precautions -- such as making sure your hard drive is in good shape -- you can often avoid many of these issues.
Below is a set of procedures we recommend. Although it would be nice if there were no "maintenance" needed when installing an update, our experience is that such maintenance can, and does, make the update process go more smoothly, and in fact has allowed us to avoid many minor problems. To be fair, these procedures will take a bit of time; however, they take less time than dealing with some of the issues they can help you avoid.
1. Before installing Panther, check your startup drive for damage, and repair it if necessary. The easiest way to do this is to boot from the OS X Install CD and run Disk Utility (from the Installer menu). Click the First Aid tab, select your hard drive in the drive/volume list, and click "Repair Disk." (If you know how, you can instead start your Mac in single-user mode and use fsck, as this runs the same repair routines.) If you have a third-party disk utility such as Alsoft's DiskWarrior, you can also run that for good measure.
2. Before installing Panther, boot from your hard drive again and repair permissions on your boot volume. To do this, launch Disk Utility (located in /Applications/Utilities), click the First Aid tab, select your hard drive in the drive/volume list, and then click "Repair Disk Permissions." (It's important that you do this while booted from your hard drive, rather than from the OS X install CD or another volume, in order to perform the "correct" repairs.)
3. Install Panther. (See the tip below, "More info for Panther upgraders," for more information about installation options.)
4. After installing Panther and then booting from your hard drive (you should now be starting up into Panther!), again repair permissions via Disk Utility as described in Step 2. This will ensure that any system-level permissions that may have been corrupted or changed incorrectly -- installers are notorious for this -- are reset to the correct values.
By following the above procedures, you're not assured a problem-free upgrade, but you'll certainly have a "healthier" installation, which may help you avoid many of the issues that befall haphazard upgraders.
More info for Panther upgraders The publishers of the well-known Mac newsletter TidBITS have announced a new ebook, Take Control of Upgrading to Panther, by Joe Kissell, that provides a much more comprehensive look at upgrading to Panther, including a discussion of the many different options offered by the Panther installer.
UPDATE: Apple also has a Knowledge Base article that focuses on troubleshooting software updates and installations.