Hi Jeff,

here is a page I found - https://support.source-elements.com/show/compatible-interfaces-that-provide-audio-drivers-that-share-between-programs-in-windows

I have a Focusrite 4i4 Gen3 USB audio interface, and audio sharing between various application works fine - as per my previous email.

I do this every day, mp3 backings tracks via VLC, or BIAB, then I load Reaper with the Line 6 VST and play guitar.

I more than happy to assist with any tests you'd like me to do. I also run Win10 with the latest patches (both on a PC and laptop). Focusrite via USB C on the laptop, standard USB 3 on the PC.

I like the Focusrite 4i4, no external power required. Prior that I had an 8i6 which gave me more options but it needed external power and was quite heavy.

Cheers, Paul