New Dell XPS 15
Enabled Hyper-V and tried to create a Server 2012 VM.
Client window was black but the preview window was displaying the correct view of the client OS.
The other fixes that appear on Google did not apply because I was in the process of setting up a new VM.

Fix:
With Hyper-V running and the client window open.
Open the NVIDIA control panel
Click on Manage 3D settings
1. select a program to customize
Select c:\windows\system32\vmconnect.exe
IF you are not able to select this, click the Add button and locate it in the displayed list of programs.
2. Select the preferred…..
Select Integrated graphics
Click Apply

Now, close the Hyper-V client window and reopen it.