You can start the batch processing service directly from a terminal. This is usually not practical for a production environment, but it can be very useful when troubleshooting problems. You can view the output of the service directly in the terminal in which you launch it as it starts and handles jobs.
In a terminal, enter the following command:
$ /Applications/Toon Boom Harmony 15.0 Advanced Network/tba/macosx/bin/tbprocess -schedule