I have on my PC an Intel 120 GB SSD (the Windows drive) and a 1 TB HDD. I want to replace the Intel 120 GB SSD with a Crucial 256 GB SSD (and after that use the Intel drive as a third drive).

How can I clone the Intel SSD to the Crucial one (after I install all of them in the PC)? I have looked for cloning software but found only software that require you to boot the system using their bootable images.

Can you clone a bootable drive while Windows is running, than simply restart the PC and use the new disk as the boot drive? If not, why? If yes, do you know any good software for doing it?

  • 1
    You can't clone an active OS, from within that OS, that's why you need to boot from another OS to perform the clone. As for software to do it: software requests are off topic for SU, but there are PLENTY of question regarding cloning HDD's and SSD's, many of which contain links to many different cloning programs for you to try. Dec 16, 2014 at 19:32
  • Thank you. My question was more like why isn't possible to clone an active OS? Is it because the files might change during copy?
    – Cristy
    Dec 16, 2014 at 19:33
  • 1
    Could you post what OS and version you're using.
    – Foxocube
    Dec 16, 2014 at 19:49
  • I thought windows like to complain a lot when you change hardware too much, is switching to a new HD ok with windows? And you could boot a linux cd/usb and do a quick dd in from the old drive/partition out to the new... but that doesn't satisfy your "while OS is running"
    – Xen2050
    Dec 16, 2014 at 19:59
  • I use Windows 7.
    – Cristy
    Dec 16, 2014 at 20:59

4 Answers 4


According to my experience with Acronis products, confirmed by this post in Acronis official forums, you could do a backup and then restore to the new ssd.
Whatever the reason for cloning while using it is, any changes made after starting the backup of the source disk, will be lost for the new drive.
Also it might not work if your source disk is almost full, as acronis needs to make a snapshot.

  • Ok, I will use the boot method. I found a small piece of paper in my crucial SSD box (which only contained the ssd itself and this paper below the plastic support. It is a link to acronis website :)
    – Cristy
    Dec 16, 2014 at 21:02
  • I did a clone using acronis. The new SSD now appears as H: and the old one as C: and it is still the system disk. How can I swap the drive letters (and also which one actually is the system disk) ? That is it will boot from the new 256GB SSD and the old one will be the H: partition so I can format it.
    – Cristy
    Dec 16, 2014 at 21:37
  • @Cristy Swap drive letters here HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices Swap H: with some thing unused z: then c: with h: and finally z: with c: Reboot.
    – cybernard
    May 28, 2018 at 17:08
  • Will it clone the drive partitions too? Do I need to set the partition first before doing this?
    – mr5
    Oct 31, 2018 at 16:57

Assuming you're running a Microsoft Windows OS, this can be achived with the use of disk2vhd and vhd2disk.

First download a copy of Disk2VHD from the Microsoft Sysinternals website.

Start up Disk2VHD and ensure the "Use Vhdx" box is not checked, and that the "Use Volume Shadow Copy" box is checked. This will resolved the issue mentioned by Techie007. Then select your C: drive (assuming this is the SSD) from the "Volumes to include" section and your destination (this would be somewhere on your 1TB HDD) in the "VHD File name" section.

Disk2VHD Screenshot

Press "Create" and let the image complete. Do not use your computer during this time, as changes and documents may be lost if they are stored on the SSD.

Once the image is complete, download VHD2Disk from the Sysinternals forums.

Load up VHD2Disk and select your VHD Image in the "VHD File name" section. You should see your boot sector and main NTFS partition in the "Volumes to include" section. Make a note of the existing drives in the "Target drive" section, then plug in your new SSD. Then select the new drive (it should be the one that's not in your list of existing drives) and click VHD to Disk.

VHD2Disk Screenshot

Once the transfer is complete, you will need to expand the data partition on the new drive to make use of the extra space.

Open the start menu, then search for and open "Disk Management". You should see your new SSD, with an empty section to the right of the data partition. Right-click the data partition and select extend volume. You can then follow the on-screen wizard, leaving all of the options at the default values. This will expand your partition to fill the new SSD.

Now shut down your PC, remove your old SSD, and boot up from your new SSD.

  • This isn't a clone, its imaging to a 3rd volume and then converting back to a drive-level file system. Why not just use Windows' Image backup then? No downloading needed for that. :) Dec 16, 2014 at 21:35
  • I do not want to remove my old SSD. The new SSD now appears as H: and the old one as C: and it is still the system disk. How can I swap the drive letters (and also which one actually is the system disk) ?
    – Cristy
    Dec 16, 2014 at 21:36
  • I would recommend temporarily removing the old SSD, so you can be sure that you are booting from the new one. Once you are sure, then you can plug the old one back in and wipe it.
    – Foxocube
    Dec 17, 2014 at 1:05

It depends what cloning software you use. Some of them provide a specific function to clone the partition on which the operating system is currently running.

The reason this is possible is that after prompting you for all the info about what cloning you want, they reboot to a special environment and perform the cloning there instead of under Windows.

You mention it's a Crucial SSD; things may have changed since the question was asked, but today Cricual SSDs come with free Acronis True Image for Crucial, which can clone the current partition as I've described. From the Acronis user guide:

enter image description here

I've just used this successfully on a new Crucial SSD:

enter image description here

Note: Acronis True Image for Crucial is just an example, and it only works if it detects a Crucial SSD, so don't waste time on it if you don't have one. I just happened to get a Crucial drive, so I used Acronis, but I'm sure there must be others, free or otherwise. For example, over a decade ago I used Norton Ghost for all my disk imaging, and that could reboot to another environment to clone the current partition in just the same way.


I've had a good experience with Macrium Reflect Free as well as with Acronis True Image for Crucial. Both are free at the time of writing.

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