OS X Beta Seed Program Hitherto, those looking to test out beta releases of Apple’s OS X would need to sign up to the Developer Program, which, for $99 per year, looked quite a steep fee for the casual, inquisitive user. Now, however, the Cupertino company has introduced a new OS X Beta Seed Program, whereby users can test out pre-release builds of the Mac software simply by signing up with an Apple ID – no annual fee required.
1 Launch Feedback Assistant Once you have enrolled your Mac for beta updates and installed the OS X 10.9.3 beta, you will find Feedback Assistant in your Dock. Enroll Your Mac 2 Sign in with your Apple ID Sign in with the same Apple ID that you used to register for the OS X Beta Seed Program. 3 Give us your feedback Reporting any issues you encounter is easy. Just fill out the step-by-step form, review your answers and diagnostic files, and send them to Apple.
Usual caveats...... Note the emphasis on the word..... Beta. OS X Beta Seed Program Backup, and backup again before downloading, and during Beta Testing
And to return to your previous version of Mavericks OS X: About OS X Recovery OS X Lion, Mountain Lion, and Mavericks include OS X Recovery. This feature includes all of the tools you need to reinstall OS X, repair your disk, and even restore from a Time Machine backup without the need for optical discs. http://support.apple.com/kb/HT4718