Using NULL as a field value

The string NULL has a particular role in scripts and is a reserved word.

The reserved word is NULL in all capital letters. A field with the value Null or null, for example, is acceptable. Only use NULL to clear out a particular field.

You should not use the term NULL as a field value in import set transform maps or anywhere in the First name or Last name fields. Also, do not use NULL in reference fields as the system interprets the value as a string contain the word NULL, not as a reserved word.