Mini-Tutorial: Reverting to an earlier version of Mac OS X
Instructions for safely performing a "downgrade" to a prior version of Mac OS X. Useful when problems appear with a new release.
When problems materialize in conjunction with an incremental update to Mac OS X, and all known workarounds have failed, or a critical issue appears that must be resolved immediately, it may be necessary to perform a reversion process and backpedal to the prior incremental version.
The process is somewhat time-consuming and will require you to restore some previous settings, but relatively straightforward. Also, note that you will need to be using Mac OS X 10.2.x or later for this process.
First, make a backup of your current Mac OS X installation, problematic as it may be. If there is a problem along the way, your valuable data will be safely intact in its current form.
Next, you'll need to perform an Archive and Install process to remove all of your current Mac OS X version's vital (and potentially problem-causing) components, and replace them with the components of a fresh copy provided by the Mac OS X disc that shipped with your system, or a retail Mac OS X disc. Unfortunately, this means you will lose some system settings and some or all third-party system add-ons.
To begin the process, insert your Mac OS X CD or DVD, as indicated above. Restart your machine and hold down the "C" key to boot from the newly inserted disc. Follow the on-screen instructions, and after accepting the license agreement, click "Options." Select "Archive and Install," and check the "Preserve User and Network Settings" option if you'd like to do so.
After the installation process is complete, you will be left with an earlier version of Mac OS X that (hopefully) does not suffer from the problems generated by the incremental Mac OS X update in question. However, you will likely want to bring your installation back up to the point of revision right before you started having problems. For instance, if you updated to Mac OS X 10.3.4 and began experiencing problems, you probably want to re-situate your system at Mac OS X 10.3.3. This simply requires re-applying the appropriate Mac OS X combo updater.
Various updates, back through Mac OS X Combo Update 10.2.5, are available from Apple's Support Download page.
Restore your settings and appropriate third-party software, and you will find your system with approximately the same status as prior to the problematic incremental update.
Your old system will be stored in folder called "Previous Systems" at the root level of your startup volume. If you would later like to delete this folder, you may need to change its permissions.
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