CSV Import update of an Item Record Generates the CSV Response error: Invalid purchaseunit reference key xx for unitstype <NULL>

CSV Import update of an Item record generates the CSV Response error: Invalid purchaseunit reference key xx for unitstype <NULL>.

The error is received when the Purchase Units field is updated without mapping the Units Type field. This is based on the scenario that the Units Type field = Null (Blank) on the Item record. To resolve this include the Units Type field in the Field Mapping as shown below:

Internal ID          =      Internal ID
Purchase Units   =     Purchase Units  
Units Type         =     Units Type

Note: In the UI, a user won't be able to select values for Stock, Purchase and Sale Units without first selecting a value in the Units field.