It occurs because when a DataClass holds a reference to a non serializable class. In your case one of your data classes will have an attribute of type ch.ivyteam.ivy.security.IUser.`ch.ivyteam.ivy.security.IUser`. The serialization problem arises as soon as the process is resumed from a persistent state. Basically when you resume a Task with data, that was not fully serializable. You can work around the error by setting the data class attribute which references the non-serizalizable value as not persistent. ![alt text][1] [1]: http://answers.axonivy.com/upfiles/nonPersistentAttribute.PNG

It occurs because when a DataClass holds a reference to a non serializable class. In your case one of your data classes will have an attribute of type ch.ivyteam.ivy.security.IUser. The serialization problem arises as soon as the process is resumed from a persistent state. Basically when you resume a Task with data, that was not fully serializable. You can work around the error by setting the data class attribute which references the non-serizalizable value as not persistent. ![alt text][1] [1]: http://answers.axonivy.com/upfiles/nonPersistentAttribute.PNG