Hi Andy, > Description of problem: I get this error when I try to load data by: > Aggregate Grids by Time > > There was an error loading the data: > java.lang.NullPointerException > > If I don't choose that data source type, I don't get an error. > Are you getting this error when you select multiple grid files and try to aggregate them or are you just selecting one file? If its just one file then you should just load it in as a Gridded Data source. If its multiple files can you send us a sample of two or more of them? You can upload them here: http://motherlode.ucar.edu/repository/entry/show/Top/Unidata/Software/IDV/Support+Uploads?entryid=e850985a-8a2c-44e3-8a05-e547cfb963a1 Thanks, Jeff Ticket Details =================== Ticket ID: HIJ-271596 Department: Support IDV Priority: Normal Status: Closed