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.

Mar 12, 2020 Connect the USB flash drive or other volume that you're using for the bootable installer. Make sure that it has at least 12GB of available storage and is formatted as Mac OS Extended. Open Terminal, which is in the Utilities folder of your Applications folder. Type or paste one of the following commands in Terminal. Once the cloning/mirroring process is completed, the user has two options. They can either use the new drive and replace the old one or use the cloned drive from USB. Download this tool to clone a Mac hard drive here. The above mentioned are few of the industry leaders for data backup as far as disk cloning or mirroring is concerned.

Download macOS

Find the appropriate download link in the upgrade instructions for each macOS version:

macOS Catalina, macOS Mojave, ormacOS High Sierra
Installers for each of these macOS versions download directly to your Applications folder as an app named Install macOS Catalina, Install macOS Mojave, or Install macOS High Sierra. If the installer opens after downloading, quit it without continuing installation. Important: 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.

OS X El Capitan
El Capitan downloads as a disk image. 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

Connect the USB flash drive or other volume that you're using for the bootable installer. Make sure that it has at least 12GB of available storage and is formatted as Mac OS Extended.
Open Terminal, which is in the Utilities folder of your Applications folder.
Type or paste one of the following commands in Terminal. These assume that the installer is still 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.
Catalina:*
Mojave:*

High Sierra:*
El Capitan:
Press Return after typing the command.
When prompted, type your administrator password and press Return again. Terminal doesn't show any characters as you type your password.
When prompted, type Y to confirm that you want to erase the volume, then press Return. Terminal shows the progress as the bootable installer is created.
When Terminal says that it's done, the volume will have the same name as the installer you downloaded, such as Install macOS Catalina. You can now quit Terminal and eject the volume.

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

Use the bootable installer

After creating the bootable installer, follow these steps to use it:

Plug the bootable installer into a compatible Mac.
Use Startup Manager or Startup Disk preferences to select the bootable installer as the startup disk, then start up from it. Your Mac will start up to macOS Recovery.
Learn about selecting a startup disk, including what to do if your Mac doesn't start up from it.
Choose your language, if prompted.
A bootable installer doesn't download macOS from the Internet, but it does require the Internet to get information specific to your Mac model, such as firmware updates. If you need to connect to a Wi-Fi network, use the Wi-Fi menu in the menu bar.
Select Install macOS (or Install OS X) from the Utilities window, then click Continue and follow the onscreen instructions.

Learn more

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

Catalina:

Mojave:

High Sierra:

El Capitan:

Clone Mac Os To Ssd

It is vitally important that you back up your Mac. Whether you do so locally using Time Machine, sending it to a cloud service, or installing a duplicate creation program (or all three). There is nothing more important than backing up your computer in case an unfortunate event happens so you don't lose your precious data.

One of the easiest methods is locally, using Time Machine. Another is by backing up your data via a cloud-based service, like Backblaze or CrashPlan. Here, we're going to explain how to clone your Mac using a program like SuperDuper! or Carbon Copy Cloner.

The difference between cloning and using Time Machine

Local backups through Time Machine, cloud-based backups, and clones all serve a great purpose to keep your data safe in case of an unfortunate even that renders your Mac useless (even temporarily). The thing that makes cloning different is that you can create a bootable copy of your entire hard drive, which means you can access everything on one Mac through another simply by exporting it to an external drive, connecting the drive to the other Mac, and then selecting it from the Startup menu.

Clones are great to have around if, for example, you have to take your Mac in for repairs, but still need to continue working while it's out. You can use the cloned copy while it's in the shop.

Most cloning programs have additional features that include the ability to make regularly scheduled backups. This is ideal since, if something happens to your computer, you aren't necessarily going to want to restore from a year-old backup. I highly recommend investing in these additional features if they are offered with the cloning program you are using (for example, SuperDuper! is free to clone, but costs a licensing fee of $28 for scheduling, smart updates, sandboxes, and scripting).

Before you start

Before you get started, make sure you have an external hard drive with enough storage to fit everything on your Mac. The smartest solution is to use a portable hard drive.

You'll also need to download and install your cloning program. I'm using SuperDuper! from Shirt Pocket for this process. Most cloning programs operate pretty much the same. They will always have a detailed how-to guide to walk you through the steps.

How to prepare your external drive to use for your clone

You'll need to start with a clean external hard drive in order to make a bootable drive for your cloned backup.

Connect your external drive into the appropriate port on your Mac.
Use Spotlight to search for the Disk Utility app.
Double-click on Disk Utility to open it.
Source: iMore
Find the hard drive under External and select it. It will usually be named after the company that made it.
Click the Erase tab at the top of the window.
Source: iMore
Name the drive something that you will remember. I renamed mine 'mbp.' You will need to remember this name when you create a bootable drive.
Select macOS Extended (Journaled) from the format list.
Click Erase.
Click Done once the process is complete.
Close the Disk Utility window.
Source: iMore

Your hard drive is now formatted for cloning your Mac.

How to make a clone of your Mac

After you've downloaded and installed your cloning program, you'll need to open it to

Mac Os Clone Usb Drive