Explanation of Error: db fails to start with Caused by: org.neo4j.token.api.NonUniqueTokenException: The PropertyKey NamedToken

When attempting to start Neo4j and one is running a Neo4j 4.0.x release and where x is ⇐2 the following error may be encountered and logged in logs\debg.log

Caused by: org.neo4j.kernel.lifecycle.LifecycleException: Component 'org.neo4j.internal.recordstorage.RecordStorageEngine$2@783ae61f' failed to initialize. Please see the attached cause exception "The PropertyKey NamedToken[name:prop1, id:321, internal:false] is not unique, it existed as null.".
        at org.neo4j.kernel.lifecycle.LifeSupport$LifecycleInstance.init(LifeSupport.java:426)
        at org.neo4j.kernel.lifecycle.LifeSupport.init(LifeSupport.java:66)
        at org.neo4j.kernel.lifecycle.LifeSupport.start(LifeSupport.java:102)
        at org.neo4j.kernel.database.Database.start(Database.java:462)
        ... 13 more
Caused by: org.neo4j.token.api.NonUniqueTokenException: The PropertyKey NamedToken[name:prop1, id:321, internal:false] is not unique, it existed as null.

This error has only been reported if your environment was previously on a Neo4j 3.5.x release and then later upgraded to 4.0.x, where x is ⇐2.

This error is addressed in Neo4j 4.0.3 forward. If you have encountered this error the workaround is to utilize neo4j-admin copy which is an offline activity and will read a database and create a new copy of the database without the errors in the underlying data/database/* files. ”’

  • Last Modified: 2020-08-03 16:12:21 UTC by Dana Canzano.
  • Relevant for Neo4j Versions: 4.0.
  • Relevant keywords upgrade.