I believe the issue is more than I expected.

I have 2 External sound cards

1. Native Instruments Komplete Audio 6

2. Edirol UA-25

The Komplete Audio 6 is fine doesn't cause an issue if I use that one for BIAB

The Edirol UA25 the issue creator (Yes I have installed latest Driver for it)

I use Komplete Audio for my Guitar running Amplitube
The Edirol for BIAB

BIAB can handle if Komplete was used for main soundcard and doesn't like Edirol UA25 as
main card.

But then again the issue is why doesn't BIAB default to internal sound card when
external isn't plugged in.

Or is this a legacy issue of older sound cards

Thanks
Lionel