This issue arises if your Windows OS uses GUID Partition Table (GPT) disks. Virtualization Station does not support converting GPT disks to Master Boot Record (MBR) disks.
You can back up the data residing on GPT disks, create new MBR disks, and then after converting you can restore this data to the MBR disks.
How to check if Windows OS uses GPT disks:
- Click "Start" > "Run"
- Type “diskpart” and click OK
- Run the command: “List disk”
- Check the GPT column