Informatica: Impacted Sessions Error

I came across an interesting error when trying to run a customised Informatica Workflow. It failed and this message appeared in the log file:

“The Repository Service marked the session or session instance as impacted, and the Integration Service is not configured to run impacted sessions”

It seems that the Session called by the Workflow had not been refreshed since its parameters were last updated. The fix was simple: Check out the Session within Workflow Manager, right-click it within the Task Developer and choose Refresh Mapping. Finally validate the session and check it back in.