Fault Handling Overview
Exceptions that occur in activities are handled asynchronously by the workflow runtime engine in a process called fault handling. Exceptions are scheduled in a queue to be handled later. If the exception type matches the one that is handled by a particular FaultHandlerActivity activity, that activity will handle the exception. If the exception cannot be handled, it is bubbled up through parent activities until it ultimately causes the termination of the workflow instance.
For more information about fault handling, see Fault Handling in Workflows.