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Boot from an encrypted USB 3.0 drive?

I have formatted a USB 3.0 drive using Disk Utility's MacOS Extended (Journaled, Encrypted). I have copied my internal disk to it using Super Duper. Now I would like to be able to boot from it. I cannot figure out how. I can set it as my startup disk using System Prefences, but that Mac still starts up from the internal drive. When I hold down the Option key while booting only the internal drive shows up. I'm using MacOS 10.8.5 on a 2013 MacBook Air. Any tips?

Posted on Nov 19, 2013 8:03 AM

18 replies

Nov 22, 2015 9:26 PM in response to Jordan klein

Everything seems to be working properly as of El Capitan. I can boot from an external encrypted USB 3.0 drive. OS X now knows to ask for its password during the boot process.

My drive showed up with the name "[Update Needed]" in the choose startup disk dialog (pressing the option key during boot) but I was still able to boot from it. I managed to get its name to appear by going into System Preferences/Security & Privacy/FileVault after booting from the drive.

Al Q

Level 1

124 points

Nov 28, 2015 11:05 AM in response to Adam Wildavsky

Thanks for the update.

First the good news: I just verified that I too can now boot my mid-2012 Macbook Pro from an encrypted clone of my boot drive (made with Super Duper!) using a USB3 drive with no intermediate USB2 hub. So with El Capitan Apple has eliminated that annoying glitch.

Now the bad news. It boots really slowly. In fact I see no significant difference in boot speed whether I connect the USB3 drive directly or through a USB2 hub. So I am pretty sure that Apple took the easy way out and chose to boot USB3 drives in USB2 mode. And the drive seems to be running at USB2 speed even after I log in, when OS X certainly has full USB3 support available.

Of course it could be that my USB3 drive is just a slow drive and it is the drive not the Mac that is limiting performance. It's a "slim" Seagate 2TB portable, so I don't expect it to be a speed demon. I will try some tests and see what I find. For its main purpose of backup, speed is less important than reliability plus small form factor that will let me carry it everywhere. I'm using .5 TB for a clone, and 1.5 TB for Time Machine.

Nov 28, 2015 5:47 PM in response to Al Q

Slow for me as well. I just ordered a 500GB external USB 3 SSD drive from Amazon for $170. I learned about it courtesy of Wirecutter.com. I'll report back on how much faster it is.

Boot from an encrypted USB 3.0 drive?