Although I prefer Linux as Desktop OS, Gaming on it is still very hard to realize. That’s why I need a Windows installation on my system. Said installation didn’t age well, so I decided to rejuvenate my six year old Windows installation and install Windows 10.

I wanted to have a fresh start and didn’t want to keep anything, but I still wanted to retain my old system and data partition as backup. I decided to use a Virtual Hard Disk (VHD) file as backup format. The advantage of this is that I can easily boot up a VM to compare my old system with my new one. Additionally Windows 7 natively supports mounting VHD, enabling easy access to the files. Thus, I created a step-by-step instruction for later reference.

Prerequisite

• For this process you will need about twice the size of your partition as disk space. The resulting image will be roughly the same size as the original.
• Of course I used Linux to do all of those steps. If you don’t have a Linux installation, use a Live USB stick with a distribution of your choice.

Backup

• unmount the partition you want to backup if it’s mounted

umount /dev/sda2

• use ntfsclone to create an image excluding unused partition space

ntfsclone -o /mnt/20160220-win_c_drive_ntfsclone.img /dev/sda2

Update 2016-03-18: I removed usage of the -s switch because it makes the resulting VHDs unreadable.

• Install VirtualBox if not already installed, we need VBoxManage

apt-get update && apt-get install --yes virtualbox

• Use VBoxManage to convert the ntfsclone image to a VHD

VBoxManage convertfromraw /mnt/20160220-win_c_drive_ntfsclone.img \
  /mnt/20160220-win_c_drive_ntfsclone.vhd --format VHD

This process may take some time, but afterwards you have your VHD backup ready to go.