thanks for your detailed answer. It looks better know, users.xml and authorizations.xml seems to be correct (what they did not before). Actually I have to go through 2 steps: First I replace in nifi.properties then line "nifi.security.user.authorizer=managed-authorizer" wicth "nifi.security.user.authorizer=file-provider" and clean authorizers.xml, leaving only file-provider and userGroupProvider. After 'cleaning' Nifi (deleting then(empty) users.xml and authorizations.xml and keystore etc.) and rebuilding with nifi-toolkit, Nifi starts and populates users.xml and authorizations.xml with reasonable entries, but stops again. Second, I undo the changes in nifi.properties and authorizers.xml and restart Nifi. It runs now stable. puh. ... View more