A family of Microsoft relational database management systems designed for ease of use.
Hi @Harold E1
In Microsoft Access, a key violation does not necessarily mean that the destination table has a primary key. It can also occur because of a unique index.
According to Microsoft’s documentation, an append query can report key violations when the data conflicts with a primary key or an index in the destination table that does not allow duplicate values.
You should therefore check the destination table in Design View > Indexes and make sure there isn't a unique index that you may have overlooked. This is also consistent with a Microsoft Q&A case where an unexpected key violation turned out to be caused by a unique index that was not initially noticed.
Also, check the table in Database Tools > Relationships to see whether it participates in any relationships with Enforce Referential Integrity enabled. An enforced relationship can prevent records from being appended if the values being inserted do not satisfy the relationship.