If you followed our advice and installed onto a secondary Mac or drive, you can just erase that volume and go back to your "real" Mac or startup drive and pretend the Yosemite beta never happened.
If for some reason you need to go back to an earlier version of OS X on your Yosemite beta Mac or drive, the easiest way is to make sure the data on that drive is backed up; erase the drive; install Mavericks onto it; and then, on first startup, use the OS X Migration Assistant to import your data from the backup.
Will I be able to upgrade directly to the final version of Yosemite when it's released this fall? Or will I have to erase my testing drive and start from scratch?
The public beta will automatically update using the Software Update mechanism used for other OS X updates! So it should be very easy.
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