As expected, Apple has released their latest desktop OS (Mojave 10.14) to the masses. Aside from setting up a new virtual machine that I use for testing the latest OSs, one of the next things I like to do is create my own bootable USB Flash Drive that I use to perform clean installs on other Macs with.
Here are the steps I followed which resulted in the successful creation of a bootable USB Flash Drive with Mojave ready to install:
Step 1: Format the USB Drive to be Bootable
This is going to format the drive so that it will be a bootable installer, without doing this the drive may not be bootable. If you don’t want to erase the drive, find one you don’t mind formatting instead. Connect the USB drive to the Mac and launch Disk Utility, then select that USB drive from the left side drive list (be sure you select the USB drive you want to make the bootable installer from) Click on the “Erase” tab and format the drive as “Mac OS Extended (Journaled), then choose “Erase” and confirm. Next go to the “Partition” tab and under ‘Partition Layout’ click on the pulldown menu, changing it from “Current” to “1 Partition”. Change the name to “Untitled” from ‘Untitled 1′ then click on the “Options” button. Choose “GUID Partition Table” as the partition scheme and choose “OK”. Click “Apply” and confirm the creation of the partition. Quit out of Disk Utility when finished. Now that the drive is ready, you can move on to making the actual installer.
Step 2: Making the macOS Mojave Installer Drive
The next step will actually make the installer drive from the previously formatted USB disk. If you already have the macOS Mojave installer application in the /Applications/ folder on the Mac, you can skip directly to the “Terminal” part. Download macOS Mojave from the Mac App Store. DO NOT INSTALL IT! When the download completes and the “Install macOS Mojave” app launches, quit out of it immediately then quit the installer. Launch Terminal app and enter the following command exactly as shown below, copy and paste works fine:
sudo /Applications/Install\ macOS\ Mojave.app/Contents/Resources/createinstallmedia –volume /Volumes/Untitled /Applications/Install\ macOS\ Mojave.app –nointeraction
Enter the administrator password when requested (this is required to use the sudo command – the password will not show up and it looks as if you’re not entering anything, that is normal behavior for the command line), then hit the RETURN key to start making the installer. You’ll see a series of message like the following, let it finish until you see the “Done” message – this may take a while as multiple GB of data have to be transferred:
“Erasing Disk: 0%… 10%… 20%… 30%…100%…
Copying installer files to disk…
Making disk bootable…
Copying boot files…
When finished and the terminal reads “Done”, exit out of Terminal, you’re ready to use the newly created bootable installer drive! Good luck!