I Ran into this issue today... After 1 hour deleted the processor and started over and then it was working fine... No idea what happened. FYI for link to guide look here: https://nifi.apache.org/docs/nifi-docs/components/org.apache.nifi/nifi-update-attribute-nar/1.9.2/org.apache.nifi.processors.attributes.UpdateAttribute/additionalDetails.html ... View more