# Issues using CDO with netCDF

**URL:** <https://forum.ecmwf.int/t/issues-using-cdo-with-netcdf/14600>\
**Category:** Datasets and Usage\
**Tags:** netcdf\
**Created:** [13 January 2026 22:21 UTC](https://forum.ecmwf.int/t/issues-using-cdo-with-netcdf/14600 "2026-01-13T22:21:37Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Christopher\_Wright](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/c/d07c76/32.png) [@Christopher\_Wright](https://forum.ecmwf.int/u/Christopher_Wright)\
**Post date:** [13 January 2026 22:21 UTC](https://forum.ecmwf.int/t/issues-using-cdo-with-netcdf/14600/1 "2026-01-13T22:21:37Z")

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Recently, my CDS downloads (always as netCDFs) have been somehow incompatible to cdo operators. A simple remapping which normally takes seconds can take hours. I’ve been able to fix the issue with a script that chunks the time dimension and alters some of the fill value attributes. Any ideas what might have happened? I don’t remember the old netCDFs doing this