Log messages from individual process instances are always sent to the server.log file, as described in About Process Engine Logging. However, these messages are mixed in with Process Engine messages as well as messages from other process instances, and it can be hard to find the specific messages you are looking for.

The Process Engine also supports process instance diagnostic logging for individual process models. When you enable process instance diagnostic logging for a process model, the process instance log messages are sent to both the server.log file and to a separate process instance log file. You can then access the process instance diagnostic log file to see the messages from an individual process instance.

For more information, see these topics: