Fixed this by discovering my date_val column had the '__HIVE_DEFAULT_PARTITION__' and then was failing on this alter because the value didn't work with the column datatype (DATE vs STRING) I got around this by changing the column to string, drop the partition for the default and then change it back to date. Got some pointers from here: http://www.ericlin.me/how-to-drop-hives-default-partition-__hive_default_partition__-with-int-partition-column ... View more