OS X El Capitan may be in Public Beta now, but that doesn't mean it's 100 percent stable.

If you want to get a taste of El Capitan but don't want to wreck your primary machine, here's how you can install it where it's not likely to cause problems.

Whether you're using the Developer Preview or the newly-released public beta, OS X El Capitan is still beta software. There will be bugs, quirks, and problems. Sure, you can install it on your primary Mac, but only if you're willing to endure any potential hiccups to your daily workflow.

If you want to skip that potential hassle and terror, I suggest using your Mac's built-in Disk Utility software to create a safe space to toy around with El Cap: a disk partition.

What's a disk partition?

When you partition your hard drive, you're essentially splitting it up into multiple autonomous parts. It's kind of like a map: If the UK were to stand in and play the part of your hard drive, England and Wales would each be separate partitions.

As such, when you create a separate partition, you can run entirely separate operating systems on it (including, yes, Windows). For our purposes, this allows you to create a small testing partition, where you can play with El Capitan without fear that a bug may cripple your day-to-day operations.

This does divide your available space up, however; if you have an 800GB hard drive and split that up into three partitions, each partition is pulling from that 800GB total.

What do I need to do before creating a disk partition?

Above all else, back up your hard drive using Time Machine or another method.

You'll also want to make sure you have enough free space for a partition; I recommend at least 30GB free for adequate testing.

How to create a partition your Mac

  1. Click on Spotlight in the upper right corner of the screen and type in Disk Utility, then select the resulting app that pops up.
  2. Select your hard drive volume in the Disk Utility sidebar. (This is the topmost hard drive icon in this list.)
  3. Click on the Partition tab.

  4. Click the + button.
  5. Size the partition with the slider based on your free space—used space is represented in blue—and give your new partition a name.

  6. Click on the Apply button.
  7. Disk Utility will then check the disk and make changes. This will take several minutes.

Once your drive is partitioned, you can install OS X El Capitan on the new partition by downloading the installer on your main partition and choosing the partition when you get to the install screen.

The El Capitan installer will give you the opportunity to import settings from your OS X Yosemite partition — as tempting as it is, don't do it. To effectively test El Cap, you should make sure to keep it a clean install. That way you know you're not introducing problems from previous installations.

How to remove your test partition

Once you're finished with your OS X beta, you have the option of removing the test partition. That said, if you have a large hard drive, it's not the worst idea in the world to have a spare partition around, especially if you're the sort of person who likes to test beta software. If you're hurting for space on your primary partition, however, and your OS X testing was a temporary measure, here's how to trash your test partition.

  1. First, make sure you've backed up any information on your test partition you wish to save.
  2. Boot into your main partition.
  3. Open Disk Utility.
  4. Select the top-level Macintosh HD.

  5. Select Partition.
  6. Highlight the partition you wish to delete and press the - button below the Partition Layout section.
  7. Press Remove.


Have you installed OS X El Capitan yet? Did you do it on your main installation, on a new partition, or using a separate hard drive all together? Let us know in the comments.