Hi Andrew, That problem is fixed in netCDF version 4.1.3 and perhaps earlier versions. Now ncids of closed netCDF files are reusable. It's only a 16-bit quantity becasue the ncid identifies both the open file ID and the group ID within the file, for netCDF-4 files, and the two 16 bit IDs are packed into one ncid. If you're going to upgrade your netCDF version, may I suggest trying the release candidate for version 4.2? It's got lots of bug fixes as well as some performance improvements: ftp://ftp.unidata.ucar.edu/pub/netcdf/netcdf-4.2-rc2.tar.gz or from the netCDF distributions page: http://www.unidata.ucar.edu/downloads/netcdf/netcdf-rc Installation instructions are here: http://www.unidata.ucar.edu/netcdf/docs_rc/building.html --Russ Russ Rew UCAR Unidata Program address@hidden http://www.unidata.ucar.edu Ticket Details =================== Ticket ID: DPK-277567 Department: Support netCDF Priority: Normal Status: Closed