Applying encryption to a VM

[CRG55]

Hi, I am runnnig VB 5.1.18 r 114002 on Windows 10 Home. I have a VM running XP that I'd like to encrypt. It has 3 virtual drives. When I go to Settings -> General -> Encryption -> Enable encryption, I get this error:

Failed to save the settings.

Cannot encrypt medium 'D:\VirtualMachines\CG-Development\Appliance-disk1.vmdk' because it has 2 children.

Result Code: VBOX_E_INVALID_OBJECT_STATE (0x80BB0007)
Component: MediumWrap
Interface: IMedium {4afe423b-43e0-e9d0-82e8-ceb307940dda}

My guess is that it can only encrypt one drive? Does that mean I just can't use encryption on this virtual machine, or that I can, but I have to remove the extra drives, or is there a way around this? (Or am I on the wrong tack completely?)

Thanks for any advice.

[Martin]

"Children" in this case refers to linked disks or snapshots. It looks like you have other disks linked to this one as base disk.

[socratis]

Besides what Martin said, which is 100% correct, I'd like to just add a warning, about the use of encryption. The encryption keys are not stored in the virtual hard disks, they're stored in the .vbox file, the VM "recipe". So, don't think that you could copy/move the encrypted HD to another VM and make it work.

Actually, it would be best if you read the whole ch. 9.31 Encryption of disk images of the User Manual. Twice.

BTW, why are you using a VMDK?