By Jason Snell

July 7, 2016 8:13 AM PT

Where should I install my iOS and macOS betas? A guide.

Note: This story has not been updated for several years.

macOS sierra is coming Thursday. Here’s where you should install it:

• Nowhere, if you aren’t willing to constantly back up all your data and take the risks of having an unstable Mac in your life for a few months
• Nowhere, if you aren’t willing to use the Feedback Assistant app to report to Apple about the bugs you’re finding
• On a secondary Mac, i.e., not the one you use to do your job every day, or
• On a separate partition on your Mac, so you can re-boot into El Capitan for safety, or
• On an external drive attached to your Mac—I bought an external SSD so I could run macOS Sierra on my iMac without messing with my existing internal drive set-up.

iOS 10 beta is also due today. Here’s where you should install it:

• Not on your main iPhone
• Not on your main iPad
• On an iOS device that you don’t rely on

The Mac has it easy—you can always reboot from a different drive if the beta software is giving you trouble. On iOS, once a device is on a beta it’s hard to revert. You’re on it for the duration. This is why you should avoid using iOS betas on your main devices until very late in the game, if ever.

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