Originally Posted by
June7
There are duplicate FamilyID values in Family and this should be a unique value.
Then there are FamilyID values in Registration that are not in Family table ID field. This will cause the referential integrity issue. You can track down all these or maybe best to start over from scratch. Delete all records. Then run Compact & Repair on the Database Tools tab. Then establish relationships. Then build forms
Should not use spaces nor punctuation/special characters in naming convention.
Also, advise not to use exact same name for multiple fields.
Have you studied an introductory tutorial on Access and/or relational database?