By Lily / Last update November 11, 2021

Why Need to Copy Operating System 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 are popular nowadays. However, the operating system can be crashed or broken all of a sudden. 

Therefore, operating system clone is a good way to keep the data safe. It copies the operating system and applications to another place such as an external hard drive so that the data can be restored immediately after the computer is crashed. Besides, copying operating system to external hard drive brings a big convenience for users.

  • Security: System clone copies the operating system and programs installed in C drive, ensuring the data is safe when the computer is crashed. It could be a big damage to users especially companies when the system cannot run and the data is lost. However, if you clone the system before, the information will be protected and the damage can be reduced.
  • High efficiency: Operating system copy to another disk or external hard drive can save much time in rebuilding a system when the system is crashed. You can use the copies to restore system directly. By the way, rebuilding a system cannot rebuild the important information before while restoring from a system copy can.
  • Old system backup: If you want to upgrade Windows, you can copy operating system to external hard drive in advance. 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.

Cloning Operating System with AOMEI Backupper

Literally, cloning an operating system to an external hard drive is copying the operating system to HDD/SSD. Thus, there are two options to work with: clone system or create a system image. In consideration of simple operation steps, here we recommend you to clone system with the easiest backup service provider - AOMEI Backupper Professional.

  • It offers you three clone modes - System Clone, Disk Clone and Partition Clone to meet your different needs.
  • It supports various storage devices, allowing you to move OS to SATA HDD/SSD, M.2 SSD, NVMe SSD, and even USB flash drive.
  • Apart from Windows 10/8.1/8/7, it is fully compatible with the newest Windows 11. You can use it to migrate Windows 11 to SSD easily.

Before you do, prepare an external hard drive, and make sure the hard drive is big enough to hold all system data.

Step 1. Click the download button below to install and launch AOMEI Backupper. Select “System Clone” under the “Clone” tab as shown in the following picture. 

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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

Step 3. After clicking “Next” at the last step, 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 4. After confirming the source partitions and destination partition, click “Start Clone” to launch the process.

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. Well, if transferring OS to SSD, checking the “SSD Alignment” option will optimize the SSD performance.

After all the operations, wait for a minute and when the process reaches 100%, click “Finish”. You have done the system clone.


Copying an operating system to an external hard drive with AOMEI Backupper will be extremely simple. You can also create a system image by using the “Backup” features. The system backup won’t interrupt your work, so you can backup it while working. In addition, it still supports cloning an SSD to a larger SSD in Windows 10/11.

AOMEI Backupper Professional is really powerful, but it does not support Windows Server OSes. If you are a Windows Server user, you can use AOMEI Backupper Server edition to backup and restore your data more flexibly.