If you are using the vMix encoder and are getting the following screen:
Unfortunately this means your Graphics Card is not Direct X10 compatible, which is advised even though the message mentions "DirectX9". You will need to look at getting a Dedicated Graphics Card that supports Direct X10 or above.
Below is the exact message that is reported on the error screen:
"Graphics hardware is not supported
DirectX9 compatible hardware required
D3DERR_INVALIDCALL: Invalid call (-2005530516)"