virtualbox.org

This may be a known issue with no plans to fix, but I didn't see anything on it so here goes.

If you're running Aero in your 4.1.x virtualbox guest and enable the remote display, you get a black screen when you connect to it. The guest itself shows everything just fine, but the computer remoting in only sees a black screen. If you mouse over a window edge the cursor changes to the little resize icon, but everything remains black. You have to disable aero in the guest first if you want to see anything with remote display. Is this a known problem?

This is due to the experimental status of WDDM in the GA. You would get the same black screen on the Guest if you set small icons in the task bar, so the orb goes out of the taskbar a bit, then start an application that uses Aero, like Solitaire. Move it so it's touching the taskbar. The window will turn black. Once you move it 1 pixel away from the orb, it will be fine. Simple overlay issue. With RDP, you just see the same problem. Check out the preview in the main GUI, it does not show you what you see in the guest itself. You will most likely see the login screen on Welcome.