I have an update query that updates values from one table to another
table. The tables are called tbl_clients_import and tbl_clients. The
first table has data from imported from another database then I use
that table to update the records in the second table

The problem is that on the first field that is set to not be null I
get a validation error that the field is null.

Neither table has any nulls for that field so I can't figure out why I
am getting the error.

The strange thing is that I have a similar query and tables for
employees and that query works fine and those tables also include
fields set not to be null.

Any ideas where I might start looking?

Thanks,

Fr. Robert