No update operation allowed without Unique Id

Error Message

Listing related items in an Access table produces:

No update operation allowed without Unique Id.

Cause

The Access table needs to have a primary key specified.

Solution or Workaround

Open the table in Access and specify the relate column as a primary key.

Open the table you wish to work with in design view and select the field you wish to designate as the primary key field. The unique index is created automatically.