You're supporting a customer workflow in Alteryx Designer that reads from a file or database and then fails partway through the run. The failure only shows up after the workflow has already started processing, and the customer says the same workflow used to work with earlier input. You need to identify whether the issue is bad source data, a schema change, or a transformation step that cannot handle the incoming records.
How would you troubleshoot a customer workflow that is failing because of bad input data from a file or database?