Reverting to an earlier version of Mac OS X

From MacFixIt.com:

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 either Mac OS X 10.2.x or Mac OS X 10.3.x to perform 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.

Just maintain a good clone using Carbon Copy Cloner. Using the "Repair Permissions and Make Bootable" options.

Hold Option and boot from the clone and run OnyX "Automate" on it and reboot.

Check it out carefully, you may be using it someday.

Keep it disconnected, even locked up if need be.


If and when a bad software update, virus, hack or whatever occurs, even a hard drive failure.

Just break out the "Clone" and option boot from it.


In the case of your computer being "owned" it's best to "C" boot from the Panther disk first and Erase w/Zero option the boot drive.
Then "Option" boot from the clone and reverse clone back.

I have been having such a problem for awhile now, and just solved it today as i will explain below. The problem began during one of the MacOSX 10.4 updates using Software Update. Once the OS got corrupted, I could not download and install any application that required my password. Every application ending in, ..."dmg" would fail verification, or would have a "codedc overrun" failure.

This is how I solved the problem:

1. I reinstalled MacOS10.4, followed by the second CD. This second CD contains "MacOSX Update Combo...10.4.2, and updates Mac OS 10.4 to OS 10.4.1, and then OS 10.4.2.

2. I Repaired Permissions using Disk Utility, restarted my iMac, and used Software Update to install the first update in the list. The update was successful, so I knew the problem had been solved. The next step was to use Software Update to check for and install all updates needed.

3. After all the updates had been installed, I Repaired Permissions one more time, and restarted my iMac.

mac computers are so good, i don't see why anyone would need to reinstall the OS!

Stick around a while. You will see. It's an imperfect world

My 10.4.10 installation repaired itself until the hard drive it was on got hosed. I was having a series of kernel panics which seemed to be software-related and involved AppleIOkit and onboard audio if I remember correctly. I was also having an issue where the Mac would not wake from sleep.

Prior to installing Leopard I cloned my 10.4.10 installation to an external drive. I booted from the clone to make sure it was at least no more unstable than the original. Lo and behold the problem was gone. Self-healing Mac, what a concept. Unfortunately the drive the clone was on is now hosed and I will have to rebuild it if I want to run any OS 9 software.