By Emily / Last Updated August 10, 2022

Why need to transfer OS to new hard drive?

Migrate to SSD

You may want to move Windows operating system to new HDD or SSD out of different reasons:

▸ After years of usage, the available storage space of your hard drive can decrease and trigger the low disk space issue. It’s not a bad choice to move OS to a large disk and use the old one as a secondary device.
▸ The Windows operating system is installed on a hard disk drive (HDD) and you want to use SSD for OS and HDD for storage when an SSD is available.
▸ The system hard drive is about to fail due to overload, service time limitation, virus, or other unknown reasons. Moving OS to new hard drive from the old one helps you avoid reinstalling operating system and personal applications.
▸ Another important reason of migrating Windows OS is to save time and effort of reinstalling and re-configuring systems and applications which are required in a clean install. To transfer OS to new drive with the help of OS migration software, you can keep system files and personal data intact.

Whatever reasons in your mind, the next step is to figure out how to move your OS to new SSD or HDD.

Powerful software to transfer OS to new hard drive 

For some files and folders, such as the Documents, Music, Photos, or Videos folder, you can drag and drop them to new hard drive in Windows Explorer. However, it is not wise to just drag and drop Windows OS-related files to the new drive because it won’t be bootable afterwards.

Thus, here we would like to introduce a secure and effective OS migration software for Windows 11/10/8/7 (32/64-bit) – AOMEI Partition Assistant Professional. Its "Migrate OS to SSD Wizard" can copy all OS-related files and all other applications & files stored on system partition from your old hard drive to the new one. After cloning, you can boot OS successfully from the new hard drive.

What’s more, if you want to transfer all data from one hard drive to another even when the target disk is smaller, you can do it easily and safely with the Disk Clone feature.

Download Demo Win 11/10/8.1/8/7/XP
Secure Download

What to do before moving OS to new hard drive?

To transfer OS to new hard drive successfully, you have to make the following preparations:

1. Connect new hard drive

First, you have to connect or install the secondary new disk to your computer. If you are using a desktop, you can install the new hard drive internally. If you are using a laptop that has only one drive bay, you'll need an external SATA-to-USB adapter, dock, or enclosure to connect your bare drive to the computer. 

sata usb

2. Check the new hard drive space

Now, you can check how much unallocated space the new hard drive comes with. It has to be larger than the boot partition on the source hard drive. If not, it is advised to delete or shrink other existing partitions to get enough unallocated space.

3. Verify the partition style of new hard drive

Since the partition style has to be compatible with the employed boot mode (UEFI & Legacy BIOS). To avoid changing boot mode after cloning, it is better to make the partition style of the new hard drive as the same as the source hard drive's. So please convert the new disk to GPT or MBR when necessary.

4. Make a backup

Back up the OS in advance for a quick recovery in case that the cloning process was interrupted by some unexpected issues such as power failure. Besides, you also have to back up everything important on the new hard drive if there are because all data will be overwritten during the cloning process.

How to transfer old OS to new hard drive step by step

After everything is ready, please refer to the steps below to see the detailed steps to migrate OS to new HDD.

Step 1. Install and open Partition Assistant Standard. Click Migrate OS to SSD in the left pane. Don’t be confused by its name because it can apply to HDD as well.

Migrate OS to SSD


Step 2. Choose the new hard drive here as the target disk. If there is a partition on SSD, check “I want to delete all partitions on the disk 2 to migrate system to the disk” and make “Next” available.

Select Disk Space


Step 3. You can drag the double-headed arrow to resize the system partition, or just type the desired number in the box below.

Resize Partition


Step 4. Read the Note in this window.



Step 5. Click Apply and Proceed to execute the pending operations.




▸ This operation involves system partition, which requires it to be completed under PreOS mode.

▸ To transfer Server OS to new hard drive, you can switch to the Server edition.

▸ To boot from the new hard drive, you need to set it as the first boot device in BIOS. Press F10 to save changes and exit.

Change Boot Order


Either to transfer OS to new hard drive out of upgrading old disk or out of replacing the failing one, AOMEI Partition Assistant Professional just let your hassle away. In the meantime, it helps you to manage partitions conveniently and overall. Basic partition operations, like Resize/Move Partition, Merge Partitions, Clone Disk/Partitions, Create/Format/Delete Partition, Split Partition, etc are provided by it.