When updating existing records via the Import process, users receive a "The Import ID field is required to update existing records" error message. Possible causes for this error includes, but are not limited to:
The import file does not have an ImportID column to link to existing constituents.
The ID being used in the import file is the Social Security Number or Constituent ID, and Use Import ID is marked on the General tab of the import.
Update existing records is marked instead of Import new records on the General tab of the import
Add ImportID as a column in the import file, populate the constituents' import IDs, and import again.
On the General tab, mark Use Social Security Number or Use Constituent ID under How do you want the system to identify existing constituents?