Yosemite is jam-packed with new features. The ability to seamlessly transition from the iPhone to the Mac, and back again, is nothing short of magic. The new Spotlight, Safari, Mail, Calendar, and iCloud apps are amazing too. But this is beta software. It will have bugs. Some programs may stop working or not be compatible. There will be issues.
In this tutorial, I will show you how to get the best of both worlds by installing Yosemite on a completely separate partition. By keeping unique partitions, you will be able to boot into Yosemite for fun or experimentation, then boot back to the stability of Mavericks if anything goes wrong.
I will show you how to:
- Use Disk Utility to partition your hard drive
- Download and Install Yosemite
- Fix an initial boot bug
- And undo it all
NOTE: This tutorial is NOT for the faint of heart. You are messing with the hard drive. There is a chance that something could go wrong. There is also a small gotcha that occurs the first time OS X restarts after installation. I will show you a fix, but it can be quite panic-inducing. I strongly urge you to read through this entire tutorial and back up your data before you begin.
Partition the Hard Drive
Launch Disk Utility and choose top most hard drive option from the left column. Choose the Partition tab from the navigation menu on the right. You will see a rectangular graph showing the current partition layout. Click the + below the graph.
The graph will split into a representation of two different drives. Select the new drive and enter Yosemite Test in the name field. Keep the format set to Mac OS Extended (Journaled). Set the size to your liking, so long as it is larger than 25 GB. Click Apply. Click Partition to confirm.
Install Yosemite to the New Partition
Go to https://appleseed.apple.com/sp/betaprogram/. Scroll down and click the Sign Up button. If you already have an AppleID, use it to log in. If not, click the Create One Now link to sign up for a free account.
Once you've signed in, scroll to the bottom of the page and click the Get OS X Yosemite Beta Redemption Code button. Follow these steps from the resulting page:
- Ensure that the Mac meets the minimum requirements to run Yosemite. It requires OS X Mavericks 10.9 or better, 2GB of RAM, and 8GB of Hard Drive space. Your partition of 25GB or greater will allow more than enough space. So just make sure you have the RAM to support it.
- Back up the Mac. You should have already done this.
- Make note of the redemption code in step 3, then click the Download OS X Yosemite Beta button.
The App Store will launch and take you to the code redemption section. Your code should entered automatically, but if it isn't enter it manually. The Yosemite Beta Installer will begin downloading. The download progress is visible from the Purchases tab.
Once downloading is complete, the installer will automatically launch. Click Continue. A backup reminder will appear. You should have backed up your data by now, so click Continue. Agree to Apple's Terms and Conditions, and when prompted for the drive to install Yosemite, click Show All Disks. Then choose Yosemite Test and click Install. Once the installation is complete, your Mac will reboot into Yosemite.
Fix the Boot Bug
Normally you would be able to toggle back and forth between partitions/operating systems by holding down option as you reboot and then choosing the partition you wish to boot into. But until you follow the steps outlined below, an option reboot will only offer up the Yosemite partition. Not your previous Mavericks install.
To fix this bug, reboot your Mac while holding down command r. This will put your Mac into recovery mode. Don't choose any of the options in recovery mode. Instead, click the red close button on the top left of the window.
Click on Choose Startup Disk from the resulting popup menu. Select your Mavericks disk, then Restart.
Your Mac will boot into Mavericks and from now on both disks will appear during a typical option reboot. You have fixed the bug and no longer need to boot into recovery mode.
Undoing It All
If you no longer want to keep Yosemite, you can undo it all in Disk Utility. All files created while using Yosemite will be deleted. So backup anything you worked on before proceeding.
From the Mavericks partition, launch Disk Utility. Click on the Yosemite Test drive then click Erase. Then click Erase to confirm.
Click on the top most disk in the left column and the partition tab on the right. Highlight the Yosemite partition at the bottom and click the - button. Click Remove to confirm, then use the graph to set your existing disk to maximum storage. Finalize everything by clicking Apply.
In this tutorial, I taught you how to enjoy Apple's first Open Beta without fear of bugs or broken apps. You learned how to partition the hard drive, install Yosemite, and undo it all if need be.
So why not give Yosemite a try and leave a comment below with your favorite new feature?
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