Problem starting Win11

[DustyDogInSpain]

I have a dual boot system of Linux Mint and Windows 11.
The two systems are on separate drives.
The boot screen allows me to select booting into Linux or Windows.

I have installed VirtualBox onto my Linux installation and am trying to open the Windows 11 system through this.
The setup involved adding a vmdk file pointing to the /dev/nvme0n1 drive which contains my Windows installation.
Everything seems to be ok but when I try to Start the virtual server I just get a GRUB screen.

Can anyone help with this?