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Converting QEMU VM to VirtualBox VM

Recently, I decided to convert my QEMU based virtual machine installed on my Manjaro Linux to the VirtualBox format. The reason behind this is that I would like to be able to use the same VM across different host system (specifically Manjaro Linux and Windows 7). It is not a easy thing to do, so I decided to document it for future references.

Prerequisite?

  • An existing image created using QEMU (My VM file end with .img, for example)
  • VirtualBox

How to?

First thing first, you would need to convert the QEMU image (extension img) to raw format, this can be done by issuing the following command:

qemu-img convert Windows7-compressed.img -O raw Windows7.raw

This will generate a raw image. Note that this newly generated file might be a lot larger than the file it based on, this is because the img file allocates space on as-is basis.

After you get the raw image, it’s time to convert it to VDI format (which is used by VirtualBox). You can do this by running:

VBoxManage convertfromraw Windows7.raw --format vdi Windows7.vdi

Then, it is recommended to compact the image:

VBoxManage modifyhd Windows7.vdi --compact

So after the previous step, you will have a working VirtualBox image, but if you boot it from VirtualBox, it might not work.

Gotchas!

In my case, what I was trying to convert was a Windows 7 VM, and when I finished the above steps and try to boot the VM, I got a BSOD. My feeling is that there were some default that QEMU used that doesn’t work for a newly created machine in VirtualBox. I tweak the following settings in the newly created VirtualBox VM:

  • Delete the auto created SATA controller and change it IDE controller.

It turned out, after doing that, everything works as expected.