Thank you PG. FWIW, I have some reason to suspect that this issue is more to do with the RME card/driver. The reason is that in my system, the RME send AES to Mytek converters. I notice that the lights on the Mytek are lit, as though it was receiving AES from the RME but WL appeared to be ‘hanging’. This might not be immediately obvious unless you are sending AES to an external converter.