How to Boot a Mac from a USB

The Apple Mac has been in circulation for 35 years now—and it feels like the great Mac vs. PC debate has been going on just as long. The playful rivalry peaked from 2006 to 2009 with the iconic “I’m a Mac, and I’m a PC” advertisements, but Apple and Microsoft have since taken a step back and allowed their fans to continue the argument in their stead.

Realistically, managed services providers (MSPs) can’t afford to choose a side. For starters, Apple represents too big a chunk of the technology industry. Apple’s 2019 first quarter reports reveal some staggering numbers:

  • Apple’s quarterly revenue reached $84.3 billion dollars
  • Their earnings per diluted share rose 7.5% to $4.18, a record high
  • Revenue from Macs grew 9%, another all-time high

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In 2018, AppleInsider reported IBM uses over 277,000 macOS and iOS devices—130,000 of them Macs. With statistics like these, it’s clear Apple is showing no signs of slowing down—it would be risking for your business if you don’t support Macs and other Apple products.

MSPs must be well-versed in Windows and Mac support to give clients the service they need when issues arise on either type of operating system. For Macs in particular, MSPs should familiarize themselves with the support required to handle Mac boot options. Take a look at our step-by-step guide to booting a Mac from a USB below.

Why do you need boot options for Mac?

The simple fact is, computers (even Macs) don’t boot up from time to time—which can be frustrating since it prevents you from getting into your system to view the problem. Booting from an external drive allows you to work around the problem and get into your internal drive to diagnose any issues.

Knowing how to boot a Mac from a USB is critical because many computers and laptops in circulation don’t have disk drives anymore, meaning the most common way to boot is now out of vogue. The latest Mac laptops don’t even have USB-A ports in them—instead, users have to buy a separate, external port that connects to a USB-C port. Knowing how to boot with a USB is a necessary part of keeping your IT best practices up-to-date.

Booting a Mac from a USB is particularly important for MSPs because it’s an agile and effective way to work. It’s unlikely all your clients will use the same type of computer or even have the same operating system, so it pays to prepare for many possible computing scenarios. Booting with a thumb drive gives you the flexibility to keep and run different versions of macOS.

Tutorial: how to boot a Mac from USB

Booting a Mac from a USB may sound complex, but it only involves three core steps. First things first—start with a fast, clean flash drive with at least 32GB of storage (ideally more). If you’re using a flash drive with data already on it, make sure you’ve backed up all files elsewhere—you’ll have to wipe the drive clean in the Mac booting process.

  1. Prepare USB drive for a Mac recovery bootAfter you’ve inserted the USB drive, open Finder and navigate to Applications > Utilities > Disk Utility. Open “Disk Utility” and you’ll see your USB listed under “External” on the left side. Select your USB, then click on the “Erase” button at the top.The “Erase” button will bring up new fields for “Name,” “Format,” and “Scheme.” Name or rename the drive to a title that is indicative of what is inside—for example, “Mac Boot Manager.” Select “Mac OS Extended (Journaled)” as the format. Once you confirm by selecting “Erase” at the bottom right, you’re finished preparing the USB.
  2. Download macOS onto a USB driveOpen the App Store, download the copy or copies of macOS you want, and install them directly onto the USB. To pick whichever version is compatible with the system you’re working with, you can access older versions of macOS by going back through your “Purchased” tab. If the version you want isn’t in the Purchased tab, you might find your desired version through the official Apple website.Unfortunately, if you’ve upgraded to Mojave or later, you can only access older versions of macOS by legally re-purchasing them.
  3. Install and run macOS from a USB driveStart by inserting the USB into your Mac’s USB port or the USB-C connector. Press the power button to turn on or restart your computer. Press and hold the “Option” key when you hear the startup sounds—this will bring you to the Startup Manager.Once the Startup Manager appears, you can release the Option key. Startup Manager will then start scanning your device for drives it can boot from, including your USB. Identify the drive you want to use by selecting and double-clicking the appropriate USB.All your files will copy onto your drive first, which takes approximately 10 minutes. Your Mac will then shut down and begin a full installation—how long that takes will depend on the speed of your hardware. With fast hardware the installation process can take as little as 10 minutes, while slower systems will take longer.

    After the installation process is complete, your Mac will reboot with a fresh version of macOS and you can set it up how you like. Connect to WiFi, supply your Apple ID information, and use your Mac as intended.

Interested in learning more about Mac management? Explore our related blog articles

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