Parts entered into the catalog database as subassembly components (i.e. they are assigned an Assembly List value) cannot be selected when we want to add them via Multiple Catalog for a one-off scenario. Entering an Assembly List value prevents us from being able to select the part via the Catalog Browser. However we can have a main part number entered more than once in the database, as long as the Assembly Code fields are different for each entry, either blank, or with various Assembly Code values to make each an unique entry. But sometimes we need to enter the same subassembly part into the database with and without an Assembly List value, so we can select it when building an assembly using the Multiple Catalog option.
The Catalog Browser edit mode will allow us to copy a row/record that is assigned an Assembly List value. We can then blank out the Assembly List field, which should then cuse the entry to be interpreted as a unique record. But when we click the Check, to save and close the Catalog Browser's Edit Mode, we receive a popup error, and we are not allowed to save the record. See screen captures below:


We can make the entry by brute force, using MS Access, but we shouldn't have to. It is dangerous to directly edit the database with MS Access, unless you possess a full understanding of how the tables must be formatted and you know how to avoid damaging the database. The average user shouldn't be forced to edit the database with MS Access.