Problem

How to include subfolders in Batch Converter.

Solution

Press SHIFT+ESC to switch to windows dialogs and enable "Include
Subdirectories".

Optional:

After a file is attached it can be edited to be set up to process a
subdirectory.

Edit the path, replace the file name with " *\* ".

Example:

If you want to process the subfolders for all DGN files in a folder

C:\folder1\folder2\:

Add a file from this path, then edit the path as follows:

c:\folder1\folder2\*\*.dgn