I'm not sure about it, as far as we're speaking about a Neo4j problem (see https://github.com/neo4j/neo4j/issues/173) first of all we should understand or ask if the blueprints project make you create the key index before or after the GraphML import. I was unable to see any bug report regarding that, so I understand the current blueprint behaviour is to create the key index before the graphml import in the case of neo4j, but I'm not sure.