That makes sense, thanks Mike.
I guess in its current format the starter app isn't useable in PinballX. Bit of a shame as it would be 'set and forget', the alternative is to use the alternateexe flag in PinballX but that does need more user maintenance.
I'll reply on the vpu thread, not sure if Jarr3 / @jrl will see this here.
Still doesn't quite explain the PinballX crash when the system using the starter app is set as Visual Pinball, if the starter app was set to stay open until vpx closes would pbx still crash?