Tip:This tutorial also applies to similar demands of copying OS from a laptop HDD/SSD to a USB pen drive. For example:

Macworld also has bootable-install-drive instructions for: mac OS High Sierra (10.13) El Capitan (OS X 10.11) Yosemite (OS X 10.10) Mavericks (OS X 10.9).
If you want to do a clean install of macOS Sierra, or you have multiple Macs to install it on, then a bootable flash drive for is your best bet for easy installation. Here’s how to make one.
Don’t be surprised by the slowness – it will take considerably longer to boot the operating system of a USB drive than the PCIe SSD installed in modern Macs. You can now run the operating system as normal and can use this USB drive to boot up your Mac if your boot drive fails.

how to transfer Windows OS from a laptop to USB drive and make it bootable?
How to install the laptop OS on an external pen drive?

Aug 11, 2019 How to install the laptop OS on an external pen drive? Why Do You Copy OS from Your Laptop to a USB Pen Drive. Portable and accessible anywhere. For example, you can easily access your work computer system from home with only a USB drive! That fully explains why you put a laptop OS on a removable storage device. In fact, other than carrying. How to Install OS X Lion from USB Pen Drive or DVD (Clean Install) OS X Lion was released today via the Official Mac App Store. Apple has limited the ways to get Lion on your Mac to only the Mac App Store.

Why Do You Copy OS from Your Laptop to a USB Pen Drive

Portable and accessible anywhere. For example, you can easily access your work computer system from home with only a USB drive!

That fully explains why you put a laptop OS on a removable storage device. In fact, other than carrying your laptop operating system elsewhere (at home, in the office or on a business trip), there is another noticeable benefit. With a bootable USB pen drive at hand, you shall feel worry-free and risk-free when accidents happen, especially the hardware failure or system blue/black screen of death that prevents you from booting up your laptop normally.

What's the Best Way to Put Your Laptop OS to a USB Pen Drive

First, let's list some viable solutions:

Windows To Go Creator.
System backup software.
System clone software.

As we know that the Windows To Go is a feature only available in Windows 8.1 Enterprise, Windows 8 Enterprise, Windows 10 Enterprise and Windows 10 Education. People running those mentioned operating system editions can use this tool to install OS on some supported USB drives. Otherwise, it's likely to receive the error 'this is a removable drive and isn't compatible with Windows To Go' and fail to create Windows To Go with non-certified USB flash drive.

By contrast, the latter two ways seem to be much easier with fewer limitations. Even though, the last way of system clone is much better!

This is what you should clearly understand between the two manners of copying OS from a laptop HDD/SSD to a USB pen drive.

First, you need to download EaseUS Todo Backup on your laptop. It's reputable Windows backup software with comprehensive solutions to system backup and system clone.

Second, the system backup way takes effect like this:
It's software associated. i.e., you can only use the software to back up the laptop operating system, in addition, restore the system from the USB pen drive via the software again.

At last, the system clone way is the simplest and most efficient. It's independently existed as long as you have transferred the operating system from the laptop to the USB drive, which means that once the bootable USB pen drive is successfully made for the first time, you can boot the laptop OS anytime on any other computer or laptop, without requiring additional tools!

How to Create a Portable USB Pen Drive with Easeus Todo Backup

USB requirements:

1. Check how much disk space is used for the system C drive. Let's assume 40GB. Then prepare a qualified USB drive, of which the disk capacity must be larger than 40GB.

2. Do you use an empty new USB drive or an old one? Make sure that all the important data has been safely transferred because the system clone will overwrite data on it completely.

3. Correctly connect the USB drive to your machine and make sure that Windows has detected it and assigned a drive letter to it.

Follow the overall process to create a portable Windows USB drive and boot from it:

Step 1. Launch EaseUS Todo Backup. Expand the menu and click 'System Clone' in the lower position.

Step 2. On the 'System clone' window, the software will choose the system partition and boot partition by default. Just Choose the USB drive as the destination disk.

Click on 'Advanced options' and then 'Create Portable Windows USB drive'. Click 'OK'.

Mac Os Install Usb

Click 'Proceed'. The software will start immediately cloning the default partitions of your desktop/laptop to the USB drive. After the cloning process is over, you can safely plug the USB drive out.

Step 3. Boot from the USB drive.

Install Mac Os Sierra

Connect your portable USB to the computer
Restart the computer and press 'Del' to enter BIOS
Set the PC to boot from the portable USB by changing the boot order in BIOS under the 'Boot' tab
Save changes and you'll see your system booting up from the USB drive

Mac Os Pen Drive Install