Are you a registered developer with Apple? Do you want to try out Mavericks without risking your entire Mac to a potentially wonky version of OS X? I haven’t seen any major issues, yet, but that doesn’t mean that mission critical softaware you rely on will work in Mavericks beta.
So, here’s the solution. Boot up from a USB stick that has been configured as a bootable OS X Mavericks drive. Here’s how.
The super smart folks at OS X Daily lay it all out, nice and simple. I’m using their stellar guide to inform this post, as there’s no reason to re-invent the wheel. Go give them a look; they’ve got some great stuff over there.
That said, let’s start in with getting Mavericks beta onto a USB drive. You’ll need at least an 8 G USB stick, or any other external hard drive that you can completely erase and use for this purpose. Also, make sure the Mac you’re using is new enough to run Mavericks beta, too. There’s a list on the Apple.com if you’re unsure.
Head over to the Apple Developer site, sign in with your Apple ID, and download a copy of OS X Mavericks beta. Don’t install it, though.
Connect your USB drive and then launch Disk Utility from the Utilities folder, which is in the Applications folder. Click on the USB drive on the left there, and click on the Partition tab. Select a single partition, and click the options menu to choose “GUID” as the partition type. Hit OK, and then click the Apply button.
Now, in order to see hidden files, issue the following command in Terminal, which you can launch from the Utilities folder, as well:
defaults write com.apple.Finder AppleShowAllFiles TRUE;\killall Finder;\say Files Revealed
Now you’ll want to find the OS X 10.9 Developer Preview app. It should be in the Applications folder. Right click (or Control-Click for you single-button mouse and trackpad users) and choose Show Package Contents from the resulting contextual menu. Open Contents, and then the SharedSupport folder.
You should see a self-mounting image called InstallESD.dmg; double click it to mount it like a regular disk. Open the now mounted disk (OS X Install ESD) image and right-click on BaseSystem.dmg. Choose Open to mount the image. If you don’t see it, you missed the step above to make hidden files visible.
Now drop back into Disk Utility and select BaseSystem.dmg from the left side, and click on the Restore tab. Set Source to BaseSystem.dmg, Destination to the USB drive (you can drag the USB drive icon into the box from the Finder, and then click the Restore button. Be sure to let it erase the drive with a quick confirmation button click.
WHen that process is done, head to the Finder and go to the newly made USB drive, and open System folder, then the Installation folder. Delete the file named Packages, and then leave the Finder window open.
Head back into the mounted OS X Install ESD drive and drag and drop the Packages folder from this disk to the Installation folder you just deleted the Packages alias from. Let stuff copy; it might take a few minutes.
Now the USB drive is ready to boot with. All you need to do is restart your Mac while holding the Option key down. When the list of available bootable drives appear, you should see your USB drive as an orange disk drive named OS X Base System 1. Click on it, and let it install from there.