So now you have the Windows 8 Developer Preview installed as a virtual machine using VirtualBox, but you found out that the guest addition of VirtualBox doesn’t work properly in Windows 8 Developer Preview, which means that it won’t auto-adjust the resolution when you resize the window, and have to stick with the resolution available by default.
No worry. There is an alternative solution to force the desired resolution to be available in the VirtualBox guest OS, so if you have done it correctly, you can now run Windows 8 Developer Preview in VirtualBox with your screen native resolution. Instructions after the jump.
Techie Talkz 