8.1->10 Upgrade: VirtualBox Graphics

[Scrappy]

I have a fully activated (CD on my desk) copy of Windows 8.1 running on Mac in VirtualBox ... I wish to upgrade to Windows 10, but when I click the icon, it tells me that it can't due to the 'VirtualBox Graphics Adapter for Windows 8' ...

I've searched high and low but so far have not been able to find anything except threads about how to install Windows 10 into VirtualBox, but nothing about upgrading ...

Has anyone successfully done this yet? Is there a way of 'disabling' the Graphics Adapter to get around this?

Windows isn't within my realm of expertise ... I'm a Mac / Unix user, and suffer with this for accounting purposes only

Thx

[mpack]

Please see existing discussions of this subject, of which I feel we already have plenty.