Some software (in my case I'm thinking of MusicIP) cannot handle file and path names that contain diacritical marks (accents, umlauts, etc.: e.g., é, â, ü, ñ). But you may already have a lot of such paths in your music folders. Here is a filter that will find all these files:
NOT %_path% MATCHES ^[a-zA-Z0-9\W_]*$