Can I Copy Windows to an External Hard Drive?

You will learn how to copy operating system to an external hard drive to protect OS and data on it. The copied OS will work perfectly.


by Lily Updated on August 22, 2023

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Why Need to Copy OS to External Hard Drive?

Operating system makes computer run and it stores a lot of important data. Now, information technology is developing at a high speed. Windows 7, Windows 8, Windows 8.1, Windows 10, and Windows 11 are popular nowadays. However, the operating system may crash or break all of a sudden

Therefore, some users choose to copy operating system to external hard drive to keep the data safe and the copied OS can be used immediately after the computer crashes. You don't need to reinstall Windows, which saves much time and effort. 

Besides, you can do so before upgrading system. Therefore, you can return to your old OS and get your data back when the new system goes wrong or you don't enjoy the new OS.

Best Software to Clone Windows to External Hard Drive

Since cloning Windows to external hard drive has so many benefits, how do we implement it? You can use excellent system clone software - AOMEI Backupper Professional. It provides you with two working ways, namely clone system or create a system image. In consideration of simple operation steps, here we recommend you clone system with this software.

And you can enjoy some useful features in the following: 

It offers you System Clone, Disk Clone and Partition Clone to meet your different needs. To clone Windows to external hard drive, you can choose System Clone or Disk Clone depending on the items you want to include and the storage space of the target disk.
It allows you to clone OS between different partition styles (MBR to GPT or GPT to MBR) while ensuring secure boot.
It is able to clone hard drive or SSD of different types, such as SATA, NVMe, PCIe, M.2, etc.
It is also capable of cloning all brands of disks, such as perform Samsung/WD/SanDisk/Seagate/PNY disk clone.

How to Copy Operating System to External Hard Drive Step by Step

First, you need to download AOMEI Backupper Professional and install it on your computer. (PS: The Clone features in free trial can only be demonstrated. Please upgrade to the full version to conduct the operation.)

Download Free Trial Win 11/10/8.1/8/7/XP
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Then, learn how to clone Windows 10 to external hard drive in detail below. The steps also apply to other PC systems. For server users, try AOMEI Backupper Server.

Step 1. Launch AOMEI Backupper. Select “System Clone” under the “Clone” tab as shown in the following picture. 

Choose System Clone

Step 2. Select the destination partition for cloning the system. Here take “Disk1” as an example, select it and click “Next”.

Choose Destination Partition

After clicking “Next”, it will pop up a window to remind you the destination partition will be overwritten or deleted. If there isn’t any data on it, click “OK” to go on, or you need to click “Cancel” to cancel the operation and backup the important data first.


Step 3. Confirm the source partitions and destination partition, and click “Start Clone” to copy Windows XP/7 to external hard drive. Well, if you are transferring OS to SSD, checking the “SSD Alignment” option will optimize the SSD performance.

System Clone Preview

You can set up more by pitching on the options in the left bottom.

  • The “Sector by sector clone” will clone all sectors from source partition to destination partition, which can also take more time to finish.
  • If you are cloning disk to larger disk, there will be one more option called "Make full use of disk space". It's to extend system partition size with unallocated space.

After all the settings, you can leave the program to finish the process in the background. When the process reaches 100%, click “Finish”. You have done the system clone.

Bonus Tip: How to Backup OS to External Hard Drive

If you want to create a backup task for your computer OS, AOMEI Backupper can also do you a favor. Just create a system image using the “System Backup” feature. The backup process won’t interrupt your work, so you can backup OS while working. With a system image at hand, you can restore system to a previous state if your computer is not responding or stops working.

System Backup


Copying an operating system to an external hard drive with AOMEI Backupper will be extremely simple. And it can further improve the SSD performance using 4k alignment technology and extend the size of system partition with its "Make full use of disk space" feature.

In addition, it still allows you to clone an SSD to a larger SSD in Windows 10, replace laptop HDD with SSD, clone SATA to NVMe, clone hard drive to Samsung SSD, etc. Anyway, it's worth-trying software for data protection.

Lily · Editor
Lily Green joined AOMEI in 2018 and has since become a professional in the areas of data protection and data transfer. She is committed to helping users protect their precious computer data and troubleshoot Windows system errors. She consistently stays vigilant about the latest trends in technology, guaranteeing that the given information aligned with the ongoing advancements in the field.