Symptoms

'Action Not Found' error when initializing form.
 

Diagnoses

The 'Action Not Found' error usually occurs when an 'Action a Worklist Item' rule on a form has an invalid or null value for its 'Action' field. This commonly occurs when customizing the 'Action Settings' on a User Task and leaving the 'Action a Worklist Item' rule in the 'When the Form is Initializing' event.
 

Resolution

The 'Action a Worklist Item' rule action was in the 'When the Form is Initializing' event. Make sure that this rule gets placed on a button or at a point where an action has been selected.