Hi @data4life 
For scenario 1, I tried running the same code, and I believe I found the issue. It's related to the %run command in NB1.

The line %run "./Folder2/NB2" assumes that Folder2 is inside Folder1, but that's not the case in your setup. So, when you run NB1 directly, it throws the same error you saw when running "main" — because NB1 can't locate Folder2 within its directory.

To fix this, try updating the line in NB1 to:
%run "../Folder2/NB2"
The .. tells it to go up one directory level, allowing it to correctly find NB2 in Folder2.

Let me know if that helps!