vmdk->vhdx

https://cloudbase.it/qemu-img-windows/

Usage examples
Convert a QCOW2, RAW, VMDK or VDI image to VHDX

qemu-img.exe convert source.img -O vhdx -o subformat=dynamic dest.vhdx

Convert a QCOW2, RAW, VMDK or VDI image to VHD

qemu-img.exe convert source.img -O vpc -o subformat=dynamic dest.vhd