Hans- You will be notified by email of any responses (like this one). I am trying to figure out how to duplicate this problem. I used your threddsConfig and catalog (but on a local dataset) and that seemed to work ok. I notice the use of ncml. Can you change the catalog (temporarily) to use the underlying datasets directly and see if the problem occurs there as well. I can fix the code to check for the null exception, but that is only palliative and really won't get at the root of the problem. =Dennis Heimbigner Unidata Ticket Details =================== Ticket ID: NHM-436259 Department: Support THREDDS Priority: Normal Status: Closed