diff --git a/BizHawk.Emulation.Cores/Consoles/Sega/gpgx/GPGXControlConverter.cs b/BizHawk.Emulation.Cores/Consoles/Sega/gpgx/GPGXControlConverter.cs
index 90bc98ddb2..ae4939b5ee 100644
--- a/BizHawk.Emulation.Cores/Consoles/Sega/gpgx/GPGXControlConverter.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Sega/gpgx/GPGXControlConverter.cs
@@ -129,6 +129,10 @@ namespace BizHawk.Emulation.Cores.Consoles.Sega.gpgx
 						DoMouseAnalog(i, player);
 						player++;
 						break;
+					case LibGPGX.INPUT_DEVICE.DEVICE_NONE:
+						break;
+					default:
+						throw new Exception("Unhandled control device!  Something needs to be implemented first.");
 				}
 			}