I have a 2 tables (tblCase and tblCaseDetail) linked via CaseID. CaseID is the Primary Key in tblCase and a foreign key in tblCaseDetail. Referential integrity is enforced and there are currently no records in tblCaseDetail. I have a form (frmCase) that is used to display data from tblCase. On frmCase I have a command button that is used to open a form (frmCaseDetail) and add data to tblCaseDetail. I keep getting the following error when I try to add data though: You cannot add or change a record because a related record is required in table 'tblCase'. I'm not sure what the issue is. I have the foreign key field set to default to the value of primary key from whatever record is open on frmCase. I purposely made the foreign key field visible on frmCaseDetail so that I could make sure it was defaulting correctly and therefore I can see the Primary Key value of the record it says doesn't exist. So, obviously the record it's saying doesn't exist DOES exist. What am I missing here?