Data Replication error in Hadoop

Question

I am implementing the Hadoop Single Node Cluster on my machine by following Michael Noll\'s tutorial and have come across data replication error:

Here\'s the full error

Answer 1

Although solved, I'm adding this for future readers. Cody's advice of inspecting the start of namenode and datanode was useful, and further investigation led me to delete the hadoop-store/dfs directory. Doing this solved this error for me.