Prerequisites for AutoLookup queries

For AutoLookup to work, certain conditions must be met:

• The query must be based on more than one table and the tables must have a one-to-many relationship. (Referential integrity doesn't have to be enforced.)
• The join field on the "one" side of the relationship must have a unique index. A unique index means that the field is a primary key or its Indexed property in table Design view is set to Yes (No Duplicates).
• The join field you add to the design grid must come from the table on the "many" side of the one-to-many relationship. (In other words, it's the foreign key for that table.) For AutoLookup to work, this field can't be a primary key and its Indexed property can't be set to Yes (No Duplicates). For example, in a query that includes the Customers and Orders tables, drag to the design grid the CustomerID field from the Orders table, not the one from the Customers table.
• The value you enter in the join field from the "many" side must already exist in the join field from the "one" side.