Head over to your installation folder and locate your 'AppConfig.xml' file (this will be in your Products/FORC-FDEV folder. The same folder as your EliteDangerous32.exe). Open this up in notepad and edit the following line:
From-
<Adapter>0</Adapter>
To-
<Adapter>1</Adapter>
Save the file, restart the game and see if that forces the adaptor. If the above is already set to '1', try setting it to '0'.