Hi Rob, I did take a quick look at your issue, but adjectives like "unpredictable" and "NFS" make the root cause more difficult to diagnose. By chance, do you know if the ncx file in the stack trace was being written at the time access was attempted? Also, which version of the software are you using? -Lansing Ticket Details =================== Ticket ID: NWR-841654 Department: Support netCDF Java Priority: Normal Status: Open