qemu-img - vhdx compatibility with Hyper-V

[Adam Baxter]

Hi,

I'm trying to use qemu-img to convert a disk image to VHDX for use on Windows 10's Hyper-V - qemu-img version 4.1.0 (v4.1.0-11789-g013a2ecf4f-dirty)

The image is https://cloud-images.ubuntu.com/minimal/releases/eoan/release/ubuntu-19.10-minimal-cloudimg-amd64.img

 'C:\Program Files\qemu\qemu-img.exe' convert C:\Users\Adam\Downloads\ubuntu-19.10-minimal-cloudimg-amd64.img -O vhdx -o subformat=fixed C:\Users\Adam\Downloads\ubuntu.vhdx (with or without subformat) results in the following error:

Checkpoint operation for 'New Virtual Machine' failed. (Virtual machine ID D8C746DE-89A4-4373-B330-471055C24F8F)

'New Virtual Machine' cannot create the storage required for the checkpoint using disk C:\Users\Adam\Downloads\ubuntu.vhdx: The requested operation could not be completed due to a virtual disk system limitation.  Virtual hard disk files must be uncompressed and unencrypted and must not be sparse. (0xC03A001A). (Virtual machine ID D8C746DE-89A4-4373-B330-471055C24F8F)

Hyper-V doesn't seem to give much more information than that - how would I go about troubleshooting this?

Regards,

Adam