How to make new T2-secured Macs boot from external drives

“Apple’s security processor gets in the way when you’re trying to [boot from] external drives,” William Gallagher writes for AppleInsider. “Fix this now because if you wait until you need to restart from one, you’ll have problems.”

“By default, Macs with the T2 processor will not boot from an external drive. That’s fine, that’s even good, but it’s an inconvenience when you want to do it,” Gallagher writes. “Then if the reason you want to boot from an external drive is a catastrophic failure of your internal one, it’s a problem”

“Truly, if you’re booting from an external then it’s to solve some problem, not to find others,” Gallagher writes. “So take a minute to fix this now, before you have to.”

Read more in the full article here.

MacDailyNews Take: Take a minute to allow booting from external media, before something catastrophic happens!

[Thanks to MacDailyNews Reader “Fred Mertz” for the heads up.]


  1. The default of restricting external boot is a bad choice for a consumer product.

    Allow it (heck, maybe even straight-up ask about it on OS installation), but to default disallow external media boot is to treat a PC like an appliance.

  2. I am not sure that this is such a good idea. The author himself admits that using the Cmd-R trick with a connected keyboard, you can still boot from an external disk. On the one hand, disabling this will allow anyone to boot your machine from an external disk, if it happens to get stolen, but YOU will also be able to boot it in case a) you have catastrophic failure of your internal disk and b) you can’t boot from recovery partition.

    The second scenario seems a lot less likely to me than having my MacBook Pro stolen. (I have had three MacBook Pros stolen, but I have never had a catastrophic failure of my hard drive where I couldn’t boot from the recovery partition).

    Also, I think the calculus here is different for various models of Mac. How likely is it that a MacBook Mini or an iMac is going to wind up in the hands of a thief? For a desktop Mac, it might very well make sense to take this precaution. A MacBook, on the other hand, presumably goes outside all the time, so you might want to think twice about disabling the extra security this mechanism provides.


  3. I book ALL my iMacs from external drives (they’re older models and use fast and cheap external SSDs).

    I can’t tell from the article, but would you have to go through this process EVERY SINGLE TIME you want to boot from an external drive?? That kinda kills the whole cheap external boot drive market, now don’t it?


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