Sql 2008 R2 on Windows 2008 R2 cluster. When I move instance from node 1 to node 2 everything is fine: all resources come online as they should. When I move the instance from node 2 to node 1, all resources except sql server and agent come online. If I delete errorlog and start the sql server service, sql server and agent startup without problems. Also, I can offline the server on node 2, move it to node 1, and try and start it but it fails unless I delete the errorlog first. I checked startup parameters and servers are identical. I also have a second instance on the same cluster and it moves back and forth between nodes without incident.