At this year’s WWDC, Apple announced the next iteration of OS X, version 10.11. Dubbed “El Capitan” after the famous landmass in Yosemite National Park, this version of OS X builds upon the roots established in 10.10 “Yosemite” to bring about performance and stability enhancements.

A week ago, El Capitan was made available in a public beta for those wishing to try out Cupertino’s latest and greatest OS simply by signing up for Appleseed, Apple’s Beta Software Program.

The update is free to use and, just like previously released OS X versions, straightforward to install. However, being in beta means that it’s still not quite ready for primetime and will likely not play nice with a host of untested (and, in some cases, unsupported) applications. Though your mileage may vary, it’s not recommended at all to install this on a production or mission-critical system.

In other words, if your life (okay, perhaps more like your work) depends on it, don’t go installing this as an upgrade to your existing OS X install. Better to err on the side of caution by installing this on a non-critical device, virtualized instance, or separate partition.

With that warning out of the way, let’s check out the requirements necessary to build a bootable installer drive for installing OS X El Capitan:

  • Apple computer with OS X 10.9+
  • Administrative credentials
  • 8 GB USB flash drive or SD card minimum
  • OS X El Capitan Public Beta Installer (Mac App Store)

Now, here are the steps:

  1. Mount the USB drive or SD card on the computer and take note of the volume name assigned.
  2. Launch from the Applications | Utilities folder and enter the following command (Figure A):
    sudo /Applications/Install\ OS\ X\ El\ Capitan\ Public\ –volume /Volumes/DRIVE_LABEL –applicationpath /Applications/Install\ OS\ X\ El\ Capitan\ Public\ –nointeraction
    Figure A
  3. When prompted, enter the admin password to execute the process (Figure B).
    Figure B
  4. The partition is erased and the installer files are copied to the drive (Figure C).
    Figure C
  5. The drive will be made bootable and the boot files transferred over as well (Figure D).
    Figure D
  6. Upon completion (and barring any fatal errors), the drive will be ready to install OS X El Capitan on supported devices. It’s best to verify that the files were written to the drive by opening the partition and checking (Figure E).
    Figure E

That’s it! Installing El Capitan for testing purposes is a great way to get the experience of what changes the new OS brings, see how that impacts existing applications and settings, and discover how well it plays in the enterprise.

Another word of warning, being a beta product means that the software will not play nice in some instances, particularly when flagging errors. Some turn out to be false positives, while others are the fault of non-optimized code. Either way, your mileage may vary.