Hi Nathan, Everything Ed said is correct. The netCDF-3 libraries are not threadsafe. Our documentation should point this out and I should also add an FAQ about it, since you are not the first developer to ask this question. --Russ Russ Rew UCAR Unidata Program address@hidden http://www.unidata.ucar.edu Ticket Details =================== Ticket ID: RNK-564883 Department: Support netCDF Priority: Normal Status: Closed