In this guide I will explain how to create a bootable USB drive with one of the following Mac operating systems.
- Os X 10.11 El Capitan
- Os X 10.12 Sierra
- Os X 10.13 High Sierra
- Os X 10.14 Mojave
First, you need a copy of the operating system you want to copy to the USB drive. Below is where to find each operating system
Mac Os X 10.11 El Capitan
Mac Os X 10.12 Sierra
Mac Os X 10.13 High Sierra
Mac Os X 10.14 Mojave
Next, you need a USB drive (at least 8GB) to copy the operating system to.
There are basically three ways to create the drive. In all three cases you need a USB drive of at least 8GB formatted as Mac OS Extended (Journaled) or, alternatively, an external disk (USB, FireWire or Thunderbolt).
Method 1 (for Terminal tinkerers).
The first method is the most complicated. To be fair, it is nothing particularly complex, but you need to type a long command carefully in Terminal, a tool that can be intimidating for less experienced users, as it is designed for system administrators and people familiar with the command line. In any case, here’s how to proceed:
- Connect the USB flash drive (or another volume), format it in Disk Utility as “OS X Extended (Journaled)” and remember the name assigned to the drive.
- Open the “Terminal” application (found in the “Utilities” subfolder of “Applications”)
- In Terminal, type the following command (use copy & paste) to start the operation (we assume the operating system installer is still in the “Downloads” folder and the USB drive has been named MyVolume):
for OS X El Capitan
sudo ~/Download/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath ~/Download/Install\ OS\ X\ El\ Capitan.app --nointeraction
for macOS Sierra
sudo ~/Download/Install\ OS\ X\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath ~/Download/Install\ OS\ X\ Sierra.app --nointeraction
for macOS High Sierra
sudo ~/Download/Install\ OS\ X\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath ~/Download/Install\ OS\ X\ High\ Sierra.app --nointeraction
for macOS Mojave
sudo ~/Download/Install\ OS\ X\ Mojave.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath ~/Download/Install\ OS\ X\ Mojave.app --nointeraction
Whichever operating system you are copying, enter the administrator password, press “Y” (yes) when prompted and, after several minutes (you need to wait while the various files are copied to disk), the USB drive will be created. Copying is complete when the message “Copy complete” appears in the Terminal window, followed by the user prompt (the username followed by the $ symbol). Bear in mind that it may take quite a few minutes (depending partly on the speed of the USB drive used). You can then close the Terminal window and eject the newly created drive.
Method 2, the simplest (with DiskMaker)
The simplest and quickest method is undoubtedly DiskMaker X, a free, long-established (available since OS X 10.7 Lion), reliable and easy-to-use application. Here’s how to proceed:
- Download the program from the developer’s website (the link is here). You can copy it to the “Applications” folder, but this is not essential. Launch the application and click “Open” to confirm opening a program downloaded from the internet. You will be asked to choose the installer to start from: Mavericks (OS X 10.9), Yosemite (10.10) or El Capitan (10.11). Click the button for the system you want to create.
- DiskMaker automatically locates the installer file to use to create the drive, showing its path in the window displayed. If the path is correct, click “Use this copy”; otherwise, click “Use another copy” and specify where you saved the installer file.
- You will then be asked what type of disk you are using. If you are using an 8GB USB drive, simply click the “An 8GB USB thumb drive” button; for other types of disk, click “Another kind of disk”. Bear in mind that the selected disk will be completely erased, so pay particular attention to what you are doing.
- Next, you need to specify the disk name, i.e. the label that will be assigned to the volume. You can enter “OS X El Capitan”, but any name will do. Of course, it is best to choose a name that lets you identify the drive when needed. Once you have entered the name, click it and then click the “Choose this disk” button.
- Before proceeding, DiskMaker warns you that the entire contents of the disk will be erased. If you are sure there is nothing important on the drive, you can proceed by clicking the “Erase then create the disk” button.
- You will then be told that you will shortly be asked for the computer’s administrator password. Click “Continue” and you will see a few windows open on screen: this is the application creating the drive. When prompted, enter the administrator password for the Mac you are using.
- You now need to wait for the files to finish copying. This may take quite a few minutes (depending partly on the speed of the USB drive used; ideally use a USB 3.0 drive if your Mac has that type of port). On the late-2012 Mac mini used for testing, it took us around 16 minutes with an old Verbatim USB drive. So be patient and don’t worry if the operation seems to take a long time.
When copying is complete, the drive is ready: it can be ejected and used to boot any Mac compatible with the operating system copied onto it.
Method 3, the alternative with Install Disk Creator
A kind of “competitor” to DiskMaker X has recently appeared. It is called “Install Disk Creator”. The procedure for creating a USB drive from the downloaded operating system installer is similar to the one we saw with DiskMaker. Here it is described below anyway:
- Download the “Install Disk Creator” application from this address. You can copy it to the “Applications” folder if you wish, but this is not essential (you can also delete it once the drive has been created).
- Launch the application. A simple window appears in which you specify the destination disk (the USB drive) and the installer to start from (just click “Select the OS X installer”). Then simply click “Create Installer” to erase the target disk and start the automatic procedure (you will be asked for the administrator password of the Mac you are using). The same applies as with the other procedures: you will need to wait patiently while the files are copied and the drive is created, which may take quite a few minutes (it took us more than 15 minutes on a Mac mini). Install Disk Creator does, however, display a progress bar so you can see how far the copying and creation process has got.
In all three cases, once the respective drive creation procedures are complete, the USB drive is ready. To boot from it, restart the computer with the drive still in a USB port, hold down the Alt key and, when prompted, choose the USB drive as the startup disk.
Enjoy!
