These advanced steps are primarily for system administrators and others who are familiar with the command line. You don't need a bootable installer to upgrade macOS or reinstall macOS, but it can be useful when you want to install on multiple computers without downloading the installer each time.

What you need to create a bootable installer

  • A USB flash drive or other secondary volume formatted as Mac OS Extended, with at least 14GB of available storage
  • A downloaded installer for macOS Big Sur, Catalina, Mojave, High Sierra, or El Capitan

Connect your USB drive to the Mac using the provided USB slots. Wait for it to be recognized and displayed on the desktop. Select the USB drive from the list in Disk Utility. Ensure it’s partitioned as “Mac OS Extended (Journaled)” under the “Partition” section in Disk Utility. A USB flash drive or other secondary volume formatted as Mac OS Extended, with at least 14GB of available storage A downloaded installer for macOS Big Sur, Catalina, Mojave, High Sierra, or El Capitan. Bootable USB Stick for mac OS X El Capitan 10.11.6 USB Flash Drive for Full OS Recovery, Upgrade Reinstall System Install USB 16GB, Green. 3.8 out of 5 stars. Get it as soon as Wed, Aug 25. FREE Shipping on orders over $25 shipped by Amazon.

Download macOS

  • Download: macOS Big Sur, macOS Catalina, macOS Mojave, or macOS High Sierra
    These download to your Applications folder as an app named Install macOS [version name]. If the installer opens after downloading, quit it without continuing installation. To get the correct installer, download from a Mac that is using macOS Sierra 10.12.5 or later, or El Capitan 10.11.6. Enterprise administrators, please download from Apple, not a locally hosted software-update server.
  • Download: OS X El Capitan
    This downloads as a disk image named InstallMacOSX.dmg. On a Mac that is compatible with El Capitan, open the disk image and run the installer within, named InstallMacOSX.pkg. It installs an app named Install OS X El Capitan into your Applications folder. You will create the bootable installer from this app, not from the disk image or .pkg installer.

Use the 'createinstallmedia' command in Terminal

  1. Connect the USB flash drive or other volume that you're using for the bootable installer.
  2. Open Terminal, which is in the Utilities folder of your Applications folder.
  3. Type or paste one of the following commands in Terminal. These assume that the installer is in your Applications folder, and MyVolume is the name of the USB flash drive or other volume you're using. If it has a different name, replace MyVolume in these commands with the name of your volume.

Big Sur:*

Catalina:*

Mojave:*

High Sierra:*

El Capitan:

* If your Mac is using macOS Sierra or earlier, include the --applicationpath argument and installer path, similar to the way this is done in the command for El Capitan.


After typing the command:

  1. Press Return to enter the command.
  2. When prompted, type your administrator password and press Return again. Terminal doesn't show any characters as you type your password.
  3. When prompted, type Y to confirm that you want to erase the volume, then press Return. Terminal shows the progress as the volume is erased.
  4. After the volume is erased, you may see an alert that Terminal would like to access files on a removable volume. Click OK to allow the copy to proceed.
  5. When Terminal says that it's done, the volume will have the same name as the installer you downloaded, such as Install macOS Big Sur. You can now quit Terminal and eject the volume.

Use the bootable installer

Mac Os On Usb Drive

Determine whether you're using a Mac with Apple silicon, then follow the appropriate steps:

Apple silicon

  1. Plug the bootable installer into a Mac that is connected to the internet and compatible with the version of macOS you're installing.
  2. Turn on your Mac and continue to hold the power button until you see the startup options window, which shows your bootable volumes.
  3. Select the volume containing the bootable installer, then click Continue.
  4. When the macOS installer opens, follow the onscreen instructions.

Intel processor

  1. Plug the bootable installer into a Mac that is connected to the internet and compatible with the version of macOS you're installing.
  2. Press and hold the Option (Alt) ⌥ key immediately after turning on or restarting your Mac.
  3. Release the Option key when you see a dark screen showing your bootable volumes.
  4. Select the volume containing the bootable installer. Then click the up arrow or press Return.
    If you can't start up from the bootable installer, make sure that the External Boot setting in Startup Security Utility is set to allow booting from external media.
  5. Choose your language, if prompted.
  6. Select Install macOS (or Install OS X) from the Utilities window, then click Continue and follow the onscreen instructions.

Learn more

A bootable installer doesn't download macOS from the internet, but it does require an internet connection to get firmware and other information specific to the Mac model.

For information about the createinstallmedia command and the arguments you can use with it, make sure that the macOS installer is in your Applications folder, then enter the appropriate path in Terminal:

Using both Windows and macOS, and suddenly mac refuses to boot. The reason behind this can be from a number of things that could go wrong. This includes system failure, bad updates, power failure, hardware failure. Unless there is a hardware problem that only can be diagnosed at the apple center you can fix your Apple computer.

It is an excellent practice always to have a bootable macOS USB, which you can easily create using macOS operating system. But since we’re here, you probably can want to make bootable USB using Windows 11 and 10. Let’s be real, and there are more Windows computers compared to MAC. Fortunately, you can use a Windows computer to create a bootable USB flash drive.

In this article, we’ll help you with the instructions to create a bootable macOS USB installation media from a Windows computer. So that you can use that USB to install or reinstall (upgrade) Apple’s macOS. You can create a macOS Catalina/sierra bootable USB using this guide to fix your operating system.

What’s needed?

You will need a few things before you get started. The first essential thing in it is a USB drive would be awesome if you use a USB 3.0, but you can get the work done using a slow USB as well. So, in contrast, you need the following things.

  1. One high-quality USB flash drive with 16GB of storage.
  2. TransMac software.
  3. MacOS operating system image (DMG file).

How to Create a macos Catalina bootable usb

The guide is simple and straightforward if you follow these steps.

Download and install TransMac on your Windows PC. It’s paid software with a 15-day trial, so you can use it within the time to create a bootable macOS USB flash drive. If you like the software and to support the developer you can buy the full version.

Plug the USB drive into your Windows computer that you’ll be using to fix your MacOS. And we are going to tell you something straightforward – backup if things are stored in USB Drive.

Step 1. Open the TransMac, and select Run as administrator. If you’re using the trial version, wait 15 seconds, and click Run.

Mac os x on usb drive

Run Macos From Usb Drive

Step 2. Use your USB drive right-click on it and select format disk format this will format the USB drive so that it can be used to store the Mac OS operating system. One thing you need to take care of that the USB drive needs in GPT partition in order to work on a Mac computer otherwise it won’t boot.

When it prompts select a name for your USB it doesn’t matter but just do it and click ok. If the formatting is completed successfully, click OK to continue.

Step 3. Again from the left sidebar right-click on the USB drive and select restore with disk image.

Step 4. Now browse to the location where the Mac OS system image file is located and click ok to load it.

Step 5. Click Yes to create the macOS USB bootable media.

Mac Os Usb Drive Not Recognized

It will take a few minutes to complete the process because the Mac Operating System is larger than any other operating system like Windows and LINUX in size. Now plug the USB drive into Mac computer in order to install, install or upgrade the operating system to the latest version of Mac OS, which can be Sierra or later.

THE TOOL CAN

  • Apple File System (APFS) volume read support.
  • Open Mac APFS/HFS/HFS+ format disk drives, flash drives, CD/DVD/Blu-ray media, HD floppies, dmg, dmgpart, sparsebundle and sparseimage files.
  • Copy files to Mac HFS+ disks and dmg images.
    Format as HFS+ for Mac .
  • Save and restore images of disks and flash drives.
  • Create, compress, expand and split dmg files.
  • Built in burner functionality to burn ISO and dmg files directly to CD/DVD/Blu-Ray.
  • Read Mac multisession and hybrid CDs.
  • View partition layout.

Install Mac Os On Usb Drive

How to create a GPT partition on a USB flash drive

If the USB flash drive is not working using TransMac, it could be still a partition problem. In this case, you want to redo the entire process again, but this time use the following steps to use the Diskpart command-line utility on Windows to create the appropriate GPT partition.

Mac Os Usb Drive Not Showing

  1. Open Command Prompt as an administrator. Type cmd in run dialog or open it from the start menu.
  2. Type the diskpart command and press Enter. This will display that is connected to your computer.
  3. Enter the list disk command to view all drives connected to your computer and press Enter. This command will show all of the partitions inside of a disc.
  4. Type the select disk command followed the number assigned for the USB flash drive (e.g., select disk 4), and press Enter. This command will select the disc partition of your choice.
  5. Enter the clean command and press Enter. This erases and formats the disc.
  6. Type the convert GPT command and press Enter. This convert master boot record to new GPT.
  7. Enter the create partition primary command and press Enter to complete the process.

Mac Os X Change Permissions On Usb Drive

Quickly create a macOS bootable USB on Windows

Run Mac Os On A Usb Drive

Mac Os On Usb Drive

Now make a bootable USB using the TransMac software (follow instructions that are given above). Now connect the USB and power on your Mac computer while holding the option key and then select the USB Flash media to run the installation.

Learn using USB on MAC (Apple support page)

Reformat Usb Drive On Mac Os

Learn more about making bootable USBs.

Make a bootable USB of Windows, Linux, Chrome and Android OS
Windows 10 Media creation tool Download and Creating Bootable USB Media

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