How to downgrade Mac OS X with Time Machine

[Thursday, May 15th]

For various reasons, including system instabilities or specific program malfunctions, a user might decide to downgrade from the latest version of the OS to a previous version. There is no direct way to do this, as Apple does not provide the tools to undo or "rollback" to a previous version. However, there are two workarounds that should accomplish the downgrade and preserve user data and settings.

One method is detailed in our tutorial "How to reinstall Mac OS X". The other involves using Time Machine to restore to a previous version of OS X.

Unfortunately in Time Machine Apple does not provide information for each backup (such as the OS version that was present in that backup), but if you know when you installed the version of the OS that you'd like to remove, you can go to a backup that's prior to that date and restore it. Newer backups of user documents should still be available on the TM drive so you can access them from the backup drive after the restore and not lose any recent document changes or creations.

Here is a brief step-by-step process:

1. With the Time Machine drive attached, startup from the Leopard DVD.
2. After selecting the language, select "Restore from Time Machine Backup..." from the Utilities menu
3. Select the attached Time Machine drive and then the desired backup to restore.
4. Click "Start" and the restore process should commence.
5. Reboot the computer when completed
6. Run a permissions check on the main hard drive with Apple's Disk Utility
7. Open Time Machine and restore user data folders that may contain newer files that were created or changed after the time of the backup that was restored.

Feedback? Late-breakers@macfixit.com.

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