There are several posts in SCN talking about workflow debugging. Most of them are manually generating an endless loop and then can launch debugger in SM50. However, if you try to debug standard workflow, you are not allowed to manual inject any endless loop in standard code. If the original developer is not so kind to leave any switchable endless loop in standard code, you have to go another way.
In this example a common debugging approach is demonstrated:
Document builder is an application provided by SAP which can allow you to generate output file with format PDF, DOCX and HTML from various input with format DOCX, HTML and TXT. The workflow is also supported. When a document is generated and released, one work flow item will be sent to the respective approver.
However during my testing, I meet with error message “Workflow without approver”, although I have maintained the approver in customizing correctly.
So I guess there must be something wrong during the agent determination of workflow runtime. In order to find the root cause I have to debug it.