This is strange. Using MonetDB4 this script ran without error, in MonetDB5 I get this error: QUERY = copy INTO my_big_table FROM 'E:/data/migrate/big_table_input-ab.tab' ERROR = !MALException:batmtime.EQ:Unexpected input type always on the second input file. Here is my script: ------------------------------------- set SCHEMA myschema; declare fname varchar(100); delete from my_big_table; -- this one is good set fname='big_table_input-aa.tab'; select fname as phase; COPY into my_big_table from 'E:/data/migrate/big_table_input-aa.tab' using delimiters '\t','\n'; -- this one will error set fname='big_table_input-ab.tab'; select fname as phase; COPY into my_big_table from 'E:/data/migrate/big_table_input-ab.tab' using delimiters '\t','\n'; select 'total amount' as phase; select count(*) from my_big_table; ------------------------------------- Yet, if I run the files one at a time, the will each load without error.